Space shuttle guidance, navigation, and control design equations. Volume 3: Guidance

NASA Technical Reports Server (NTRS)

1973-01-01

Space shuttle guidance, navigation, and control design equations are presented. The space-shuttle mission includes three relatively distinct guidance phases which are discussed; atmospheric boost, which is characterized by an adaptive guidance law; extra-atmospheric activities; and re-entry activities, where aerodynamic surfaces are the principal effectors. Guidance tasks include pre-maneuver targeting and powered flight guidance, where powered flight is defined to include the application of aerodynamic forces as well as thruster forces. A flow chart which follows guidance activities throughout the mission from the pre-launch phase through touchdown is presented. The main guidance programs and subroutines used in each phase of a typical rendezvous mission are listed. Detailed software requirements are also presented.

Phase III Simplified Integrated Test (SIT) results - Space Station ECLSS testing

NASA Technical Reports Server (NTRS)

Roberts, Barry C.; Carrasquillo, Robyn L.; Dubiel, Melissa Y.; Ogle, Kathryn Y.; Perry, Jay L.; Whitley, Ken M.

1990-01-01

During 1989, phase III testing of Space Station Freedom Environmental Control and Life Support Systems (ECLSS) began at Marshall Space Flight Center (MSFC) with the Simplified Integrated Test. This test, conducted at the MSFC Core Module Integration Facility (CMIF), was the first time the four baseline air revitalization subsystems were integrated together. This paper details the results and lessons learned from the phase III SIT. Future plans for testing at the MSFC CMIF are also discussed.

Husimi function and phase-space analysis of bilayer quantum Hall systems at ν = 2/λ

NASA Astrophysics Data System (ADS)

Calixto, M.; Peón-Nieto, C.

2018-05-01

We propose localization measures in phase space of the ground state of bilayer quantum Hall systems at fractional filling factors , to characterize the three quantum phases (shortly denoted by spin, canted and ppin) for arbitrary -isospin λ. We use a coherent state (Bargmann) representation of quantum states, as holomorphic functions in the 8-dimensional Grassmannian phase-space (a higher-dimensional generalization of the Haldane’s 2-dimensional sphere ). We quantify the localization (inverse volume) of the ground state wave function in phase-space throughout the phase diagram (i.e. as a function of Zeeman, tunneling, layer distance, etc, control parameters) with the Husimi function second moment, a kind of inverse participation ratio that behaves as an order parameter. Then we visualize the different ground state structure in phase space of the three quantum phases, the canted phase displaying a much higher delocalization (a Schrödinger cat structure) than the spin and ppin phases, where the ground state is highly coherent. We find a good agreement between analytic (variational) and numeric diagonalization results.

Phase space holes and synchronized BGK modes in autoresonantly driven, Penning-trapped electron clouds

NASA Astrophysics Data System (ADS)

Friedland, Lazar; Fajans, Joel; Bertsche, Will; Wurtele, Jonathan

2003-10-01

We study excitation and control of BGK modes in pure electron plasmas in a Penning trap. We apply an oscillating external potential with a negatively chirped frequency. This drive resonates with, and phase-locks to, a group of axially bouncing electrons in the trap. All initially phase-locked electrons remain phase-locked during the chirp (the autoresonance phenomenon), while some new particles are added to the resonant group, as the bucket moves through the phase space. This creates an oscillating in space and slowly evolving in energy hole in the phase space distribution of the electrons. The electron density perturbation associated with this evolving hole yields a BGK mode synchronized with the drive. The local depth of the hole in phase space, and, thus, the amplitude of the mode are controlled by the external parameter (the driving frequency). The process is reversible, so that the BGK mode can be returned to its nearly initial state, by reversing the direction of variation of the driving frequency. A kinetic theory of this excitation process is developed. The theory uses results on passage through, and capture into, bounce resonance in the system from Monte Carlo simulations of resonant bucket dynamics. We discuss the dependence of the excited BGK mode on the drive frequency chirp rate and other plasma parameters and compare these predictions with experiments.

Phase-space reaction network on a multisaddle energy landscape: HCN isomerization.

PubMed

Li, Chun-Biu; Matsunaga, Yasuhiro; Toda, Mikito; Komatsuzaki, Tamiki

2005-11-08

By using the HCN/CNH isomerization reaction as an illustrative vehicle of chemical reactions on multisaddle energy landscapes, we give explicit visualizations of molecular motions associated with a straight-through reaction tube in the phase space inside which all reactive trajectories pass from one basin to another, with eliminating recrossing trajectories in the configuration space. This visualization provides us with a chemical intuition of how chemical species "walk along" the reaction-rate slope in the multidimensional phase space compared with the intrinsic reaction path in the configuration space. The distinct nonergodic features in the two different HCN and CNH wells can be easily demonstrated by a section of Poincare surface of section in those potential minima, which predicts in a priori the pattern of trajectories residing in the potential well. We elucidate the global phase-space structure which gives rise to the non-Markovian dynamics or the dynamical correlation of sequential multisaddle chemical reactions. The phase-space structure relevant to the controllability of the product state in chemical reactions is also discussed.

Active control of bright electron beams with RF optics for femtosecond microscopy

DOE PAGES

Williams, J.; Zhou, F.; Sun, T.; ...

2017-08-01

A frontier challenge in implementing femtosecond electron microscopy is to gain precise optical control of intense beams to mitigate collective space charge effects for significantly improving the throughput. In this paper, we explore the flexible uses of an RF cavity as a longitudinal lens in a high-intensity beam column for condensing the electron beams both temporally and spectrally, relevant to the design of ultrafast electron microscopy. Through the introduction of a novel atomic grating approach for characterization of electron bunch phase space and control optics, we elucidate the principles for predicting and controlling the phase space dynamics to reach optimalmore » compressions at various electron densities and generating conditions. We provide strategies to identify high-brightness modes, achieving ~100 fs and ~1 eV resolutions with 10 6 electrons per bunch, and establish the scaling of performance for different bunch charges. These results benchmark the sensitivity and resolution from the fundamental beam brightness perspective and also validate the adaptive optics concept to enable delicate control of the density-dependent phase space structures to optimize the performance, including delivering ultrashort, monochromatic, high-dose, or coherent electron bunches.« less

Active control of bright electron beams with RF optics for femtosecond microscopy

PubMed Central

Williams, J.; Zhou, F.; Sun, T.; Tao, Z.; Chang, K.; Makino, K.; Berz, M.; Duxbury, P. M.; Ruan, C.-Y.

2017-01-01

A frontier challenge in implementing femtosecond electron microscopy is to gain precise optical control of intense beams to mitigate collective space charge effects for significantly improving the throughput. Here, we explore the flexible uses of an RF cavity as a longitudinal lens in a high-intensity beam column for condensing the electron beams both temporally and spectrally, relevant to the design of ultrafast electron microscopy. Through the introduction of a novel atomic grating approach for characterization of electron bunch phase space and control optics, we elucidate the principles for predicting and controlling the phase space dynamics to reach optimal compressions at various electron densities and generating conditions. We provide strategies to identify high-brightness modes, achieving ∼100 fs and ∼1 eV resolutions with 106 electrons per bunch, and establish the scaling of performance for different bunch charges. These results benchmark the sensitivity and resolution from the fundamental beam brightness perspective and also validate the adaptive optics concept to enable delicate control of the density-dependent phase space structures to optimize the performance, including delivering ultrashort, monochromatic, high-dose, or coherent electron bunches. PMID:28868325

Cost effective management of space venture risks

NASA Technical Reports Server (NTRS)

Giuntini, Ronald E.; Storm, Richard E.

1986-01-01

The development of a model for the cost-effective management of space venture risks is discussed. The risk assessment and control program of insurance companies is examined. A simplified system development cycle which consists of a conceptual design phase, a preliminary design phase, a final design phase, a construction phase, and a system operations and maintenance phase is described. The model incorporates insurance safety risk methods and reliability engineering, and testing practices used in the development of large aerospace and defense systems.

Positional control of space robot manipulator

NASA Astrophysics Data System (ADS)

Kurochkin, Vladislav; Shymanchuk, Dzmitry

2018-05-01

In this article the mathematical model of a planar space robot manipulator is under study. The space robot manipulator represents a solid body with attached manipulators. The system of equations of motion is determined using the Lagrange's equations. The control problem concerning moving the robot to a given point and return it to a given trajectory in the phase space is solved. Changes of generalized coordinates and necessary control actions are plotted for a specific model.

Space Station Freedom environmental control and life support system phase 3 simplified integrated test detailed report

NASA Technical Reports Server (NTRS)

Roberts, B. C.; Carrasquillo, R. L.; Dubiel, M. Y.; Ogle, K. Y.; Perry, J. L.; Whitley, K. M.

1990-01-01

A description of the phase 3 simplified integrated test (SIT) conducted at the Marshall Space Flight Center (MSFC) Core Module Integration Facility (CMIF) in 1989 is presented. This was the first test in the phase 3 series integrated environmental control and life support systems (ECLSS) tests. The basic goal of the SIT was to achieve full integration of the baseline air revitalization (AR) subsystems for Space Station Freedom. Included is a description of the SIT configuration, a performance analysis of each subsystem, results from air and water sampling, and a discussion of lessons learned from the test. Also included is a full description of the preprototype ECLSS hardware used in the test.

Phase space manipulation in high-brightness electron beams

NASA Astrophysics Data System (ADS)

Rihaoui, Marwan M.

Electron beams have a wide range of applications, including discovery science, medicine, and industry. Electron beams can also be used to power next-generation, high-gradient electron accelerators. The performances of some of these applications could be greatly enhanced by precisely tailoring the phase space distribution of the electron beam. The goal of this dissertation is to explore some of these phase space manipulations. We especially focus on transformations capable of tailoring the beam current distribution. Specifically, we investigate a beamline exchanging phase space coordinates between the horizontal and longitudinal degrees of freedom. The key components necessary for this beamline were constructed and tested. The preliminary beamline was used as a singleshot phase space diagnostics and to produce a train of picoseconds electron bunches. We also investigate the use of multiple electron beams to control the transverse focusing. Our numerical and analytical studies are supplemented with experiments performed at the Argonne Wakefield Accelerator.

Development of control systems for space shuttle vehicles. Volume 2: Appendixes

NASA Technical Reports Server (NTRS)

Stone, C. R.; Chase, T. W.; Kiziloz, B. M.; Ward, M. D.

1971-01-01

A launch phase random normal wind model is presented for delta wing, two-stage, space shuttle control system studies. Equations, data, and simulations for conventional launch studies are given as well as pitch and lateral equations and data for covariance analyses of the launch phase of MSFC vehicle B. Lateral equations and data for North American 130G and 134D are also included along with a high-altitude abort simulation.

New thermodynamical force in plasma phase space that controls turbulence and turbulent transport.

PubMed

Itoh, Sanae-I; Itoh, Kimitaka

2012-01-01

Physics of turbulence and turbulent transport has been developed on the central dogma that spatial gradients constitute the controlling parameters, such as Reynolds number and Rayleigh number. Recent experiments with the nonequilibrium plasmas in magnetic confinement devices, however, have shown that the turbulence and transport change much faster than global parameters, after an abrupt change of heating power. Here we propose a theory of turbulence in inhomogeneous magnetized plasmas, showing that the heating power directly influences the turbulence. New mechanism, that an external source couples with plasma fluctuations in phase space so as to affect turbulence, is investigated. A new thermodynamical force in phase-space, i.e., the derivative of heating power by plasma pressure, plays the role of new control parameter, in addition to spatial gradients. Following the change of turbulence, turbulent transport is modified accordingly. The condition under which this new effect can be observed is also evaluated.

Artificial gravity as a multi-system countermeasure: effects on cognitive function.

PubMed

Seaton, Kimberly A; Slack, Kelley J; Sipes, Walter; Bowie, Kendra

2007-07-01

The Space Flight Cognitive Assessment Tool for Windows (WinSCAT) is used on the International Space Station to evaluate cognitive functioning after physical insult or trauma. The current study uses WinSCAT to assess cognitive functioning in a space flight analog (bed rest) environment where intermittent artificial gravity (AG) is being tested as a countermeasure. Fifteen male subjects (8 treatment, 7 control), who participated in 21 days of 6 degree head-down tilt bed rest, were assessed during the acclimatization phase, bed rest phase, and recovery phase. Individual differences were found within both the treatment and control groups. The treatment group accounted for more off-nominal WinSCAT scores than the control group. The length of time spent in bed rest was not associated with a change in cognitive function. Individual differences in underlying cognitive ability and motivation level are other possible explanations for the current findings.

Langley's CSI evolutionary model: Phase 2

NASA Technical Reports Server (NTRS)

Horta, Lucas G.; Reaves, Mercedes C.; Elliott, Kenny B.; Belvin, W. Keith; Teter, John E.

1995-01-01

Phase 2 testbed is part of a sequence of laboratory models, developed at NASA Langley Research Center, to enhance our understanding on how to model, control, and design structures for space applications. A key problem with structures that must perform in space is the appearance of unwanted vibrations during operations. Instruments, design independently by different scientists, must share the same vehicle causing them to interact with each other. Once in space, these problems are difficult to correct and therefore, prediction via analysis design, and experiments is very important. Phase 2 laboratory model and its predecessors are designed to fill a gap between theory and practice and to aid in understanding important aspects in modeling, sensor and actuator technology, ground testing techniques, and control design issues. This document provides detailed information on the truss structure and its main components, control computer architecture, and structural models generated along with corresponding experimental results.

New Thermodynamical Force in Plasma Phase Space that Controls Turbulence and Turbulent Transport

PubMed Central

Itoh, Sanae-I.; Itoh, Kimitaka

2012-01-01

Physics of turbulence and turbulent transport has been developed on the central dogma that spatial gradients constitute the controlling parameters, such as Reynolds number and Rayleigh number. Recent experiments with the nonequilibrium plasmas in magnetic confinement devices, however, have shown that the turbulence and transport change much faster than global parameters, after an abrupt change of heating power. Here we propose a theory of turbulence in inhomogeneous magnetized plasmas, showing that the heating power directly influences the turbulence. New mechanism, that an external source couples with plasma fluctuations in phase space so as to affect turbulence, is investigated. A new thermodynamical force in phase-space, i.e., the derivative of heating power by plasma pressure, plays the role of new control parameter, in addition to spatial gradients. Following the change of turbulence, turbulent transport is modified accordingly. The condition under which this new effect can be observed is also evaluated. PMID:23155481

New Thermodynamical Force in Plasma Phase Space that Controls Turbulence and Turbulent Transport

NASA Astrophysics Data System (ADS)

Itoh, Sanae-I.; Itoh, Kimitaka

2012-11-01

Physics of turbulence and turbulent transport has been developed on the central dogma that spatial gradients constitute the controlling parameters, such as Reynolds number and Rayleigh number. Recent experiments with the nonequilibrium plasmas in magnetic confinement devices, however, have shown that the turbulence and transport change much faster than global parameters, after an abrupt change of heating power. Here we propose a theory of turbulence in inhomogeneous magnetized plasmas, showing that the heating power directly influences the turbulence. New mechanism, that an external source couples with plasma fluctuations in phase space so as to affect turbulence, is investigated. A new thermodynamical force in phase-space, i.e., the derivative of heating power by plasma pressure, plays the role of new control parameter, in addition to spatial gradients. Following the change of turbulence, turbulent transport is modified accordingly. The condition under which this new effect can be observed is also evaluated.

Investigation of the low flux servo-controlled limit of a co-phased interferometer

NASA Astrophysics Data System (ADS)

Damé, Luc; Derrien, Marc; Kozlowski, Mathias; Merdjane, Mohamed

2018-04-01

This paper, "Investigation of the low flux servo-controlled limit of a co-phased interferometer," was presented as part of International Conference on Space Optics—ICSO 1997, held in Toulouse, France.

NCC simulation model. Phase 2: Simulating the operations of the Network Control Center and NCC message manual

NASA Technical Reports Server (NTRS)

Benjamin, Norman M.; Gill, Tepper; Charles, Mary

1994-01-01

The network control center (NCC) provides scheduling, monitoring, and control of services to the NASA space network. The space network provides tracking and data acquisition services to many low-earth orbiting spacecraft. This report describes the second phase in the development of simulation models for the FCC. Phase one concentrated on the computer systems and interconnecting network.Phase two focuses on the implementation of the network message dialogs and the resources controlled by the NCC. Performance measures were developed along with selected indicators of the NCC's operational effectiveness.The NCC performance indicators were defined in terms of the following: (1) transfer rate, (2) network delay, (3) channel establishment time, (4) line turn around time, (5) availability, (6) reliability, (7) accuracy, (8) maintainability, and (9) security. An NCC internal and external message manual is appended to this report.

Analysis of a display and control system man-machine interface concept. Volume 1: Final technical report

NASA Technical Reports Server (NTRS)

Karl, D. R.

1972-01-01

An evaluation was made of the feasibility of utilizing a simplified man machine interface concept to manage and control a complex space system involving multiple redundant computers that control multiple redundant subsystems. The concept involves the use of a CRT for display and a simple keyboard for control, with a tree-type control logic for accessing and controlling mission, systems, and subsystem elements. The concept was evaluated in terms of the Phase B space shuttle orbiter, to utilize the wide scope of data management and subsystem control inherent in the central data management subsystem provided by the Phase B design philosophy. Results of these investigations are reported in four volumes.

Dead space and slope indices from the expiratory carbon dioxide tension-volume curve.

PubMed

Kars, A H; Bogaard, J M; Stijnen, T; de Vries, J; Verbraak, A F; Hilvering, C

1997-08-01

The slope of phase 3 and three noninvasively determined dead space estimates derived from the expiratory carbon dioxide tension (PCO2) versus volume curve, including the Bohr dead space (VD,Bohr), the Fowler dead space (VD,Fowler) and pre-interface expirate (PIE), were investigated in 28 healthy control subjects, 12 asthma and 29 emphysema patients (20 severely obstructed and nine moderately obstructed) with the aim to establish diagnostic value. Because breath volume and frequency are closely related to CO2 elimination, the recording procedures included varying breath volumes in all subjects during self-chosen/natural breathing frequency, and fixed frequencies of 10, 15 and 20 breaths x min(-1) with varying breath volumes only in the healthy controls. From the relationships of the variables with tidal volume (VT), the values at 1 L were estimated to compare the groups. The slopes of phase 3 and VD,Bohr at 1 L VT showed the most significant difference between controls and patients with asthma or emphysema, compared to the other two dead space estimates, and were related to the degree of airways obstruction. Discrimination between no-emphysema (asthma and controls) and emphysema patients was possible on the basis of a plot of intercept and slope of the relationship between VD,Bohr and VT. A combination of both the slope of phase 3 and VD,Bohr of a breath of 1 L was equally discriminating. The influence of fixed frequencies in the controls did not change the results. The conclusion is that Bohr dead space in relation to tidal volume seems to have diagnostic properties separating patients with asthma from patients with emphysema with the same degree of airways obstruction. Equally discriminating was a combination of both phase 3 and Bohr dead space of a breath of 1 L. The different pathophysiological mechanisms in asthma and emphysema leading to airways obstruction are probably responsible for these results.

Phase-change materials handbook

NASA Technical Reports Server (NTRS)

Hale, D. V.; Hoover, M. J.; Oneill, M. J.

1972-01-01

Handbook describes relationship between phase-change materials and more conventional thermal control techniques and discusses materials' space and terrestrial applications. Material properties of most promising phase-change materials and purposes and uses of metallic filler materials in phase-change material composites are provided.

SSME digital control design characteristics

NASA Technical Reports Server (NTRS)

Mitchell, W. T.; Searle, R. F.

1985-01-01

To protect against a latent programming error (software fault) existing in an untried branch combination that would render the space shuttle out of control in a critical flight phase, the Backup Flight System (BFS) was chartered to provide a safety alternative. The BFS is designed to operate in critical flight phases (ascent and descent) by monitoring the activities of the space shuttle flight subsystems that are under control of the primary flight software (PFS) (e.g., navigation, crew interface, propulsion), then, upon manual command by the flightcrew, to assume control of the space shuttle and deliver it to a noncritical flight condition (safe orbit or touchdown). The problems associated with the selection of the PFS/BFS system architecture, the internal BFS architecture, the fault tolerant software mechanisms, and the long term BFS utility are discussed.

Space station contamination control study: Internal combustion, phase 1

NASA Technical Reports Server (NTRS)

Ruggeri, Robert T.

1987-01-01

Contamination inside Space Station modules was studied to determine the best methods of controlling contamination. The work was conducted in five tasks that identified existing contamination control requirements, analyzed contamination levels, developed outgassing specification for materials, wrote a contamination control plan, and evaluated current materials of offgassing tests used by NASA. It is concluded that current contamination control methods can be made to function on the Space Station for up to 1000 days, but that current methods are deficient for periods longer than about 1000 days.

Shuttle: forever young?

PubMed

Sietzen, Frank

2002-01-01

NASA has started a 4-phase program of upgrades designed to increase safety and extend use of the space shuttles through the year 2020. Phase I is aimed at improving vehicle safety and supporting the space station. Phase II is aimed at combating obsolescence and includes a checkout launch and control system and protection from micrometeoroids and orbital debris. Phase III is designed to expand or enhance the capabilities of the shuttle and includes development of an auxiliary power unit, avionics, a channel-wall nozzle, extended nose landing gear, long-life fuel cells, a nontoxic orbital maneuvering system/reaction control system, and a water membrane evaporator. Phase IV is aimed at design of system changes that would alter the shuttle mold line and configuration; projects include a five-segment solid rocket booster, liquid flyback boosters, and a crew escape module.

Low-cost Active Structural Control Space Experiment (LASC)

NASA Technical Reports Server (NTRS)

Robinett, Rush; Bukley, Angelia P.

1992-01-01

The DOE Lab Director's Conference identified the need for the DOE National Laboratories to actively and aggressively pursue ways to apply DOE technology to problems of national need. Space structures are key elements of DOD and NASA space systems and a space technology area in which DOE can have a significant impact. LASC is a joint agency space technology experiment (DOD Phillips, NASA Marshall, and DOE Sandia). The topics are presented in viewgraph form and include the following: phase 4 investigator testbed; control of large flexible structures in orbit; INFLEX; Controls, Astrophysics; and structures experiments in space; SARSAT; and LASC mission objectives.

Transverse emittance and phase space program developed for use at the Fermilab A0 Photoinjector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thurman-Keup, R.; Johnson, A.S.; Lumpkin, A.H.

2011-03-01

The Fermilab A0 Photoinjector is a 16 MeV high intensity, high brightness electron linac developed for advanced accelerator R&D. One of the key parameters for the electron beam is the transverse beam emittance. Here we report on a newly developed MATLAB based GUI program used for transverse emittance measurements using the multi-slit technique. This program combines the image acquisition and post-processing tools for determining the transverse phase space parameters with uncertainties. An integral part of accelerator research is a measurement of the beam phase space. Measurements of the transverse phase space can be accomplished by a variety of methods includingmore » multiple screens separated by drift spaces, or by sampling phase space via pepper pots or slits. In any case, the measurement of the phase space parameters, in particular the emittance, can be drastically simplified and sped up by automating the measurement in an intuitive fashion utilizing a graphical interface. At the A0 Photoinjector (A0PI), the control system is DOOCS, which originated at DESY. In addition, there is a library for interfacing to MATLAB, a graphically capable numerical analysis package sold by The Mathworks. It is this graphical package which was chosen as the basis for a graphical phase space measurement system due to its combination of analysis and display capabilities.« less

Full complex spatial filtering with a phase mostly DMD. [Deformable Mirror Device

NASA Technical Reports Server (NTRS)

Florence, James M.; Juday, Richard D.

1991-01-01

A new technique for implementing fully complex spatial filters with a phase mostly deformable mirror device (DMD) light modulator is described. The technique combines two or more phase-modulating flexure-beam mirror elements into a single macro-pixel. By manipulating the relative phases of the individual sub-pixels within the macro-pixel, the amplitude and the phase can be independently set for this filtering element. The combination of DMD sub-pixels into a macro-pixel is accomplished by adjusting the optical system resolution, thereby trading off system space bandwidth product for increased filtering flexibility. Volume in the larger dimensioned space, space bandwidth-complex axes count, is conserved. Experimental results are presented mapping out the coupled amplitude and phase characteristics of the individual flexure-beam DMD elements and demonstrating the independent control of amplitude and phase in a combined macro-pixel. This technique is generally applicable for implementation with any type of phase modulating light modulator.

Active Control of Flexible Space Structures Using the Nitinol Shape Memory Actuators

DTIC Science & Technology

1987-10-01

number) FIELD !GROUP SUBGROUP I Active Control, Nitinol Actuators, Space Structures 9. ABSTRACT (Continue on reverse if necessary and identify by block...number) Summarizes research progress in the feasibility demonstration of active vibration control using Nitinol shape memory actuators. Tests on...FLEXIBLE SPACE STRUCTURES USING NITINOL SHAPE MEMORY ACTUATORS FINAL REPORT FOR PHASE I SDIO CONTRACT #F49620-87-C-0035 0 BY DR. AMR M. BAZ KARIM R

Design and Stability of an On-Orbit Attitude Control System Using Reaction Control Thrusters

NASA Technical Reports Server (NTRS)

Hall, Robert A.; Hough, Steven; Orphee, Carolina; Clements, Keith

2015-01-01

Principles for the design and stability of a spacecraft on-orbit attitude control system employing on-off Reaction Control System (RCS) thrusters is presented. Both the vehicle dynamics and the control system actuators are inherently nonlinear, hence traditional linear control system design approaches are not directly applicable. This paper has three main aspects: It summarizes key RCS control System design principles from the Space Shuttle and Space Station programs, it demonstrates a new approach to develop a linear model of a phase plane control system using describing functions, and applies each of these to the initial development of the NASA's next generation of upper stage vehicles. Topics addressed include thruster hardware specifications, phase plane design and stability, jet selection approaches, filter design metrics, and automaneuver logic.

Horizon: A Proposal for Large Aperture, Active Optics in Geosynchronous Orbit

NASA Technical Reports Server (NTRS)

Chesters, Dennis; Jenstrom, Del

2000-01-01

In 1999, NASA's New Millennium Program called for proposals to validate new technology in high-earth orbit for the Earth Observing-3 (NMP EO3) mission to fly in 2003. In response, we proposed to test a large aperture, active optics telescope in geosynchronous orbit. This would flight-qualify new technologies for both Earth and Space science: 1) a future instrument with LANDSAT image resolution and radiometric quality watching continuously from geosynchronous station, and 2) the Next Generation Space Telescope (NGST) for deep space imaging. Six enabling technologies were to be flight-qualified: 1) a 3-meter, lightweight segmented primary mirror, 2) mirror actuators and mechanisms, 3) a deformable mirror, 4) coarse phasing techniques, 5) phase retrieval for wavefront control during stellar viewing, and 6) phase diversity for wavefront control during Earth viewing. Three enhancing technologies were to be flight- validated: 1) mirror deployment and latching mechanisms, 2) an advanced microcontroller, and 3) GPS at GEO. In particular, two wavefront sensing algorithms, phase retrieval by JPL and phase diversity by ERIM International, were to sense optical system alignment and focus errors, and to correct them using high-precision mirror mechanisms. Active corrections based on Earth scenes are challenging because phase diversity images must be collected from extended, dynamically changing scenes. In addition, an Earth-facing telescope in GEO orbit is subject to a powerful diurnal thermal and radiometric cycle not experienced by deep-space astronomy. The Horizon proposal was a bare-bones design for a lightweight large-aperture, active optical system that is a practical blend of science requirements, emerging technologies, budget constraints, launch vehicle considerations, orbital mechanics, optical hardware, phase-determination algorithms, communication strategy, computational burdens, and first-rate cooperation among earth and space scientists, engineers and managers. This manuscript presents excerpts from the Horizon proposal's sections that describe the Earth science requirements, the structural -thermal-optical design, the wavefront sensing and control, and the on-orbit validation.

Fine manipulation of sound via lossy metamaterials with independent and arbitrary reflection amplitude and phase.

PubMed

Zhu, Yifan; Hu, Jie; Fan, Xudong; Yang, Jing; Liang, Bin; Zhu, Xuefeng; Cheng, Jianchun

2018-04-24

The fine manipulation of sound fields is critical in acoustics yet is restricted by the coupled amplitude and phase modulations in existing wave-steering metamaterials. Commonly, unavoidable losses make it difficult to control coupling, thereby limiting device performance. Here we show the possibility of tailoring the loss in metamaterials to realize fine control of sound in three-dimensional (3D) space. Quantitative studies on the parameter dependence of reflection amplitude and phase identify quasi-decoupled points in the structural parameter space, allowing arbitrary amplitude-phase combinations for reflected sound. We further demonstrate the significance of our approach for sound manipulation by producing self-bending beams, multifocal focusing, and a single-plane two-dimensional hologram, as well as a multi-plane 3D hologram with quality better than the previous phase-controlled approach. Our work provides a route for harnessing sound via engineering the loss, enabling promising device applications in acoustics and related fields.

Asymmetrical booster ascent guidance and control system design study. Volume 1: Summary. [space shuttle development

NASA Technical Reports Server (NTRS)

Williams, F. E.; Lemon, R. S.; Jaggers, R. F.; Wilson, J. L.

1974-01-01

Dynamics and control, stability, and guidance analyses are summarized for the asymmetrical booster ascent guidance and control system design studies, performed in conjunction with space shuttle planning. The mathematical models developed for use in rigid body and flexible body versions of the NASA JSC space shuttle functional simulator are briefly discussed, along with information on the following: (1) space shuttle stability analysis using equations of motion for both pitch and lateral axes; (2) the computer program used to obtain stability margin; and (3) the guidance equations developed for the space shuttle powered flight phases.

Space Station ECLSS Integration Analysis

NASA Technical Reports Server (NTRS)

1993-01-01

The Space Station Environmental Control and Life Support System (ECLSS) contract with NASA MSFC covered the time frame from 9 May 1985 to 31 Dec. 1992. The contract roughly covered the period of Space Station Freedom (SSF) development from early Phase B through Phase C/D Critical Design Review (CDR). During this time, McDonnell Douglas Aerospace-Huntsville (formerly McDonnell Douglas Space Systems Company) performed an analytical support role to MSFC for the development of analytical math models and engineering trade studies related to the design of the ECLSS for the SSF.

Experimental demonstration of a phased-array antenna optically controlled with phase and time delays.

PubMed

Dolfi, D; Joffre, P; Antoine, J; Huignard, J P; Philippet, D; Granger, P

1996-09-10

The experimental demonstration and the far-field pattern characterization of an optically controlled phased-array antenna are described. It operates between 2.5 and 3.5 GHz and is made of 16 radiating elements. The optical control uses a two-dimensional architecture based on free-space propagation and on polarization switching by N spatial light modulators of p × p pixels. It provides 2(N-1) time-delay values and an analog control of the 0 to 2π phase for each of the p × p signals feeding the antenna (N = 5, p = 4).

Design and Stability of an On-Orbit Attitude Control System Using Reaction Control Thrusters

NASA Technical Reports Server (NTRS)

Hall, Robert A.; Hough, Steven; Orphee, Carolina; Clements, Keith

2016-01-01

Basic principles for the design and stability of a spacecraft on-orbit attitude control system employing on-off Reaction Control System (RCS) thrusters are presented. Both vehicle dynamics and the control system actuators are inherently nonlinear, hence traditional linear control system design approaches are not directly applicable. This paper has two main aspects: It summarizes key RCS design principles from earlier NASA vehicles, notably the Space Shuttle and Space Station programs, and introduces advances in the linear modelling and analyses of a phase plane control system derived in the initial development of the NASA's next upper stage vehicle, the Exploration Upper Stage (EUS). Topics include thruster hardware specifications, phase plane design and stability, jet selection approaches, filter design metrics, and RCS rotational maneuver logic.

Preparation of pigments for space-stable thermal control coatings

NASA Technical Reports Server (NTRS)

Campbell, W. B.; Smith, R. G.

1972-01-01

The identification and control of vapor phase reaction kinetics to produce pigments by homogeneous nucleation were achieved. A vapor phase apparatus was designed, fabricated, and calibrated through 1800 C. Vapor phase reactions were analyzed, calculations made, and powders of alumina, rutile, zinc orthotitanate (in a mixed phase), calcium tungstate, and lanthana were produced by homogeneous nucleation. Electron microscopy shows uniform particle morphology and size, and supports anticipated advantages of vapor-phase homogeneous nucleation; namely, purity, freedom from defects, and uniform particle sizing without grinding.

RF kicker cavity to increase control in common transport lines

DOEpatents

Douglas, David R.; Ament, Lucas J. P.

2017-04-18

A method of controlling e-beam transport where electron bunches with different characteristics travel through the same beam pipe. An RF kicker cavity is added at the beginning of the common transport pipe or at various locations along the common transport path to achieve independent control of different bunch types. RF energy is applied by the kicker cavity kicks some portion of the electron bunches, separating the bunches in phase space to allow independent control via optics, or separating bunches into different beam pipes. The RF kicker cavity is operated at a specific frequency to enable kicking of different types of bunches in different directions. The phase of the cavity is set such that the selected type of bunch passes through the cavity when the RF field is at a node, leaving that type of bunch unaffected. Beam optics may be added downstream of the kicker cavity to cause a further separation in phase space.

Large space telescope, phase A. Volume 5: Support systems module

NASA Technical Reports Server (NTRS)

1972-01-01

The development and characteristics of the support systems module for the Large Space Telescope are discussed. The following systems and described: (1) thermal control, (2) electrical, (3) communication and data landing, (4) attitude control system, and (5) structural features. Analyses of maintainability and reliability considerations are included.

Phase space flow of particles in squeezed states

NASA Technical Reports Server (NTRS)

Ceperley, Peter H.

1994-01-01

The manipulation of noise and uncertainty in squeezed states is governed by the wave nature of the quantum mechanical particles in these states. This paper uses a deterministic model of quantum mechanics in which real guiding waves control the flow of localized particles. This model will be used to examine the phase space flow of particles in typical squeezed states.

Rocket experiment METS Microwave Energy Transmission in Space

NASA Astrophysics Data System (ADS)

Kaya, N.; Matsumoto, H.; Akiba, R.

A METS (Microwave Energy Transmission in Space) rocket experiment is being planned by the SPS (Solar Power Satellite) Working Group at the Institute of Space and Astronautical Science (ISAS) in Japan for the forthcoming International Space Year (ISY), 1992. The METS experiment is an advanced version of our MINIX rocket experiment. This paper describes the conceptual design for the METS rocket experiment. Aims are to verify the feasibility of a newly developed microwave energy transmission system designed for use in space and to study nonlinear effects of the microwave energy beam on space plasma. A high power microwave (936 W) will be transmitted by a new phase-array antenna from a mother rocket to a separate target (daughter rocket) through the Earth's ionospheric plasma. The active phased-array system has the capability of being able to focus the microwave energy at any spatial point by individually controlling the digital phase shifters.

Rocket experiment METS - Microwave Energy Transmission in Space

NASA Astrophysics Data System (ADS)

Kaya, N.; Matsumoto, H.; Akiba, R.

A Microwave Energy Transmission in Space (METS) rocket experiment is being planned by the Solar Power Satellite Working Group at the Institute of Space and Astronautical Science in Japan for the forthcoming International Space Year, 1992. The METS experiment is an advanced version of the previous MINIX rocket experiment (Matsumoto et al., 1990). This paper describes a conceptual design of the METS rocket experiment. It aims at verifying a newly developed microwave energy transmission system for space use and to study nonlinear effects of the microwave energy beam in the space plasma environment. A high power microwave of 936 W will be transmitted by the new phased-array antenna from a mother rocket to a separated target (daughter rocket) through the ionospheric plasma. The active phased-array system has a capability of focusing the microwave energy around any spatial point by controlling the digital phase shifters individually.

Teleoperator technology and system development, volume 1

NASA Technical Reports Server (NTRS)

1972-01-01

A two phase approach was undertaken to: (1) evaluate the performance of a general-purpose anthropomorphic manipulator with various controllers and display arrangements, (2) identify basic technical limitations of existing teleoperator designs, and associated controls and displays, and (3) identify, through experimentation, the effects that controls and displays have on the performance of an anthropomorphic manipulator. In Phase 1 the NASA-furnished manipulators, controls and displays were integrated with the remote maneuvering unit; in Phase 2 experiments were defined and performed to assess the utility of teleoperators for 6 typical space inspection, maintenance and repair tasks.

A study of space-rated connectors using a robot end-effector

NASA Technical Reports Server (NTRS)

Nguyen, Charles C.

1995-01-01

The main research activities have been directed toward the study of the Robot Operated Materials Processing System (ROMPS), developed at GSFC under a flight project to investigate commercially promising in-space material processes and to design reflyable robot automated systems to be used in the above processes for low-cost operations. The research activities can be divided into two phases. Phase 1 dealt with testing of ROMPS robot mechanical interfaces and compliant device using a Stewart Platform testbed and Phase 2 with computer simulation study of the ROMPS robot control system. This report provides a summary of the results obtained in Phase 1 and Phase 2.

Phase and Pupil Amplitude Recovery for JWST Space-Optics Control

NASA Technical Reports Server (NTRS)

Dean, B. H.; Zielinski, T. P.; Smith, J. S.; Bolcar, M. R.; Aronstein, D. L.; Fienup, J. R.

2010-01-01

This slide presentation reviews the phase and pupil amplitude recovery for the James Webb Space Telescope (JWST) Near Infrared Camera (NIRCam). It includes views of the Integrated Science Instrument Module (ISIM), the NIRCam, examples of Phase Retrieval Data, Ghost Irradiance, Pupil Amplitude Estimation, Amplitude Retrieval, Initial Plate Scale Estimation using the Modulation Transfer Function (MTF), Pupil Amplitude Estimation vs lambda, Pupil Amplitude Estimation vs. number of Images, Pupil Amplitude Estimation vs Rotation (clocking), and Typical Phase Retrieval Results Also included is information about the phase retrieval approach, Non-Linear Optimization (NLO) Optimized Diversity Functions, and Least Square Error vs. Starting Pupil Amplitude.

Autonomous Satellite Command and Control Through the World Wide Web. Phase 3

NASA Technical Reports Server (NTRS)

Cantwell, Brian; Twiggs, Robert

1998-01-01

The Automated Space System Experimental Testbed (ASSET) system is a simple yet comprehensive real-world operations network being developed. Phase 3 of the ASSET Project was January-December 1997 and is the subject of this report. This phase permitted SSDL and its project partners to expand the ASSET system in a variety of ways. These added capabilities included the advancement of ground station capabilities, the adaptation of spacecraft on-board software, and the expansion of capabilities of the ASSET management algorithms. Specific goals of Phase 3 were: (1) Extend Web-based goal-level commanding for both the payload PI and the spacecraft engineer. (2) Support prioritized handling of multiple (PIs) Principle Investigators as well as associated payload experimenters. (3) Expand the number and types of experiments supported by the ASSET system and its associated spacecraft. (4) Implement more advanced resource management, modeling and fault management capabilities that integrate the space and ground segments of the space system hardware. (5) Implement a beacon monitoring test. (6) Implement an experimental blackboard controller for space system management. (7) Further define typical ground station developments required for Internet-based remote control and for full system automation of the PI-to-spacecraft link. Each of those goals are examined. Significant sections of this report were also published as a conference paper. Several publications produced in support of this grant are included as attachments. Titles include: 1) Experimental Initiatives in Space System Operations; 2) The ASSET Client Interface: Balancing High Level Specification with Low Level Control; 3) Specifying Spacecraft Operations At The Product/Service Level; 4) The Design of a Highly Configurable, Reusable Operating System for Testbed Satellites; 5) Automated Health Operations For The Sapphire Spacecraft; 6) Engineering Data Summaries for Space Missions; and 7) Experiments In Automated Health Assessment And Notification For The Sapphire Microsatellite.

Altered astronaut lower limb and mass center kinematics in downward jumping following space flight

NASA Technical Reports Server (NTRS)

Newman, D. J.; Jackson, D. K.; Bloomberg, J. J.

1997-01-01

Astronauts exposed to the microgravity conditions encountered during space flight exhibit postural and gait instabilities upon return to earth that could impair critical postflight performance. The aim of the present study was to determine the effects of microgravity exposure on astronauts' performance of two-footed jump landings. Nine astronauts from several Space Shuttle missions were tested both preflight and postflight with a series of voluntary, two-footed downward hops from a 30-cm-high step. A video-based, three-dimensional motion-analysis system permitted calculation of body segment positions and joint angular displacements. Phase-plane plots of knee, hip, and ankle angular velocities compared with the corresponding joint angles were used to describe the lower limb kinematics during jump landings. The position of the whole-body center of mass (COM) was also estimated in the sagittal plane using an eight-segment body model. Four of nine subjects exhibited expanded phase-plane portraits postflight, with significant increases in peak joint flexion angles and flexion rates following space flight. In contrast, two subjects showed significant contractions of their phase-plane portraits postflight and three subjects showed insignificant overall changes after space flight. Analysis of the vertical COM motion generally supported the joint angle results. Subjects with expanded joint angle phase-plane portraits postflight exhibited larger downward deviations of the COM and longer times from impact to peak deflection, as well as lower upward recovery velocities. Subjects with postflight joint angle phase-plane contraction demonstrated opposite effects in the COM motion. The joint kinematics results indicated the existence of two contrasting response modes due to microgravity exposure. Most subjects exhibited "compliant" impact absorption postflight, consistent with decreased limb stiffness and damping, and a reduction in the bandwidth of the postural control system. Fewer subjects showed "stiff" behavior after space flight, where contractions in the phase-plane portraits pointed to an increase in control bandwidth. The changes appeared to result from adaptive modifications in the control of lower limb impedance. A simple 2nd-order model of the vertical COM motion indicated that changes in the effective vertical stiffness of the legs can predict key features of the postflight performance. Compliant responses may reflect inflight adaptation due to altered demands on the postural control system in microgravity, while stiff behavior may result from overcompensation postflight for the presumed reduction in limb stiffness inflight.

SYNCHROTRON RADIO FREQUENCY PHASE CONTROL SYSTEM

DOEpatents

Plotkin, M.; Raka, E.C.; Snyder, H.S.

1963-05-01

A system for canceling varying phase changes introduced by connecting cables and control equipment in an alternating gradient synchrotron is presented. In a specific synchrotron embodiment twelve spaced accelerating stations for the proton bunches are utilized. In order to ensure that the protons receive their boost or kick at the exact instant necessary it is necessary to compensate for phase changes occurring in the r-f circuitry over the wide range of frequencies dictated by the accelerated velocities of the proton bunches. A constant beat frequency is utilized to transfer the r-f control signals through the cables and control equipment to render the phase shift constant and readily compensable. (AEC)

Experimental demonstration of electron longitudinal-phase-space linearization by shaping the photoinjector laser pulse.

PubMed

Penco, G; Danailov, M; Demidovich, A; Allaria, E; De Ninno, G; Di Mitri, S; Fawley, W M; Ferrari, E; Giannessi, L; Trovó, M

2014-01-31

Control of the electron-beam longitudinal-phase-space distribution is of crucial importance in a number of accelerator applications, such as linac-driven free-electron lasers, colliders and energy recovery linacs. Some longitudinal-phase-space features produced by nonlinear electron beam self- fields, such as a quadratic energy chirp introduced by geometric longitudinal wakefields in radio-frequency (rf) accelerator structures, cannot be compensated by ordinary tuning of the linac rf phases nor corrected by a single high harmonic accelerating cavity. In this Letter we report an experimental demonstration of the removal of the quadratic energy chirp by properly shaping the electron beam current at the photoinjector. Specifically, a longitudinal ramp in the current distribution at the cathode linearizes the longitudinal wakefields in the downstream linac, resulting in a flat electron current and energy distribution. We present longitudinal-phase-space measurements in this novel configuration compared to those typically obtained without longitudinal current shaping at the FERMI linac.

Fault-tolerant control of large space structures using the stable factorization approach

NASA Technical Reports Server (NTRS)

Razavi, H. C.; Mehra, R. K.; Vidyasagar, M.

1986-01-01

Large space structures are characterized by the following features: they are in general infinite-dimensional systems, and have large numbers of undamped or lightly damped poles. Any attempt to apply linear control theory to large space structures must therefore take into account these features. Phase I consisted of an attempt to apply the recently developed Stable Factorization (SF) design philosophy to problems of large space structures, with particular attention to the aspects of robustness and fault tolerance. The final report on the Phase I effort consists of four sections, each devoted to one task. The first three sections report theoretical results, while the last consists of a design example. Significant results were obtained in all four tasks of the project. More specifically, an innovative approach to order reduction was obtained, stabilizing controller structures for plants with an infinite number of unstable poles were determined under some conditions, conditions for simultaneous stabilizability of an infinite number of plants were explored, and a fault tolerance controller design that stabilizes a flexible structure model was obtained which is robust against one failure condition.

Influence of control parameters on the joint tracking performance of a coaxial weld vision system

NASA Technical Reports Server (NTRS)

Gangl, K. J.; Weeks, J. L.

1985-01-01

The first phase of a series of evaluations of a vision-based welding control sensor for the Space Shuttle Main Engine Robotic Welding System is described. The robotic welding system is presently under development at the Marshall Space Flight Center. This evaluation determines the standard control response parameters necessary for proper trajectory of the welding torch along the joint.

Out-reach in-space technology experiments program: Control of flexible robot manipulators in zero gravity, experiment definition phase

NASA Technical Reports Server (NTRS)

Phillips, Warren F.

1989-01-01

The results obtained show that it is possible to control light-weight robots with flexible links in a manner that produces good response time and does not induce unacceptable link vibrations. However, deflections induced by gravity cause large static position errors with such a control system. For this reason, it is not possible to use this control system for controlling motion in the direction of gravity. The control system does, on the other hand, have potential for use in space. However, in-space experiments will be needed to verify its applicability to robots moving in three dimensions.

Spacecraft flight control with the new phase space control law and optimal linear jet select

NASA Technical Reports Server (NTRS)

Bergmann, E. V.; Croopnick, S. R.; Turkovich, J. J.; Work, C. C.

1977-01-01

An autopilot designed for rotation and translation control of a rigid spacecraft is described. The autopilot uses reaction control jets as control effectors and incorporates a six-dimensional phase space control law as well as a linear programming algorithm for jet selection. The interaction of the control law and jet selection was investigated and a recommended configuration proposed. By means of a simulation procedure the new autopilot was compared with an existing system and was found to be superior in terms of core memory, central processing unit time, firings, and propellant consumption. But it is thought that the cycle time required to perform the jet selection computations might render the new autopilot unsuitable for existing flight computer applications, without modifications. The new autopilot is capable of maintaining attitude control in the presence of a large number of jet failures.

Methods, systems and apparatus for controlling third harmonic voltage when operating a multi-space machine in an overmodulation region

DOEpatents

Perisic, Milun; Kinoshita, Michael H; Ranson, Ray M; Gallegos-Lopez, Gabriel

2014-06-03

Methods, system and apparatus are provided for controlling third harmonic voltages when operating a multi-phase machine in an overmodulation region. The multi-phase machine can be, for example, a five-phase machine in a vector controlled motor drive system that includes a five-phase PWM controlled inverter module that drives the five-phase machine. Techniques for overmodulating a reference voltage vector are provided. For example, when the reference voltage vector is determined to be within the overmodulation region, an angle of the reference voltage vector can be modified to generate a reference voltage overmodulation control angle, and a magnitude of the reference voltage vector can be modified, based on the reference voltage overmodulation control angle, to generate a modified magnitude of the reference voltage vector. By modifying the reference voltage vector, voltage command signals that control a five-phase inverter module can be optimized to increase output voltages generated by the five-phase inverter module.

Fluid Phase Separation (FPS) experiment for flight on the shuttle in a Get Away Special (GAS) canister: Design and fabrication

NASA Technical Reports Server (NTRS)

1990-01-01

The separation of fluid phases in microgravity environments is of importance to environmental control and life support systems (ECLSS) and materials processing in space. A successful fluid phase separation experiment will demonstrate a proof of concept for the separation technique and add to the knowledge base of material behavior. The phase separation experiment will contain a premixed fluid that will be exposed to a microgravity environment. After the phase separation of the compound has occurred, small samples of each of the species will be taken for analysis on Earth. By correlating the time of separation and the temperature history of the fluid, it will be possible to characterize the process. The phase separation experiment is totally self-contained, with three levels of containment on all fluids, and provides all necessary electrical power and control. The controller regulates the temperature of the fluid and controls data logging and sampling. An astronaut-activated switch will initiate the experiment and an unmaskable interrupt is provided for shutdown. The experiment has been integrated into space available on a manifested Get Away Special (GAS) experiment, CONCAP 2, part of the Consortium for Materials Complex Autonomous Payload (CAP) Program, scheduled for STS 42 in April 1991. Presented here are the design and the production of a fluid phase separation experiment for rapid implementation at low cost.

Multipurpose exciter with low phase noise

NASA Technical Reports Server (NTRS)

Conroy, B.; Le, D.

1989-01-01

Results of an effort to develop a lower-cost exciter with high stability, low phase noise, and controllable phase and frequency for use in Deep Space Network and Goldstone Solar System Radar applications are discussed. Included is a discussion of the basic concept, test results, plans, and concerns.

Thermal Control Working Group report

NASA Technical Reports Server (NTRS)

Haslett, Robert; Mahefkey, E. Thomas

1986-01-01

The Thermal Control Working Group limited its evaluation to issues associated with Earth orbiting and planetary spacecraft with power levels up to 50 kW. It was concluded that the space station technology is a necessary precursor but does not meet S/C 2000 needs (life, high heat flux, long term cryogenics, and survivability). Additional basic and applied research are required (fluid/materials compatibility and two phase system modeling). Scaling, the key issue, must define accelerated life test criteria. The two phase systems require 0g to 1 g correlation. Additional ground test beds are required and combined space environment tests of materials.

Technology demonstrator program for Space Station Environmental Control Life Support System

NASA Technical Reports Server (NTRS)

Adams, Alan M.; Platt, Gordon K.; Claunch, William C.; Humphries, William R.

1987-01-01

The main objectives and requirements of the NASA/Marshall Space Flight Center Technology Demonstration Program are discussed. The program consists of a comparative test and a 90-day manned system test to evaluate an Environmental Control and Life Support System (ECLSS). In the comparative test phase, 14 types of subsystems which perform oxygen and water reclamation functions are to be examined in terms of performance maintenance/service requirements, reliability, and safety. The manned chamber testing phase involves a four person crew using a partial ECLSS for 90 days. The schedule for the program and the program hardware requirements are described.

Microgravity fluid management in two-phase thermal systems

NASA Technical Reports Server (NTRS)

Parish, Richard C.

1987-01-01

Initial studies have indicated that in comparison to an all liquid single phase system, a two-phase liquid/vapor thermal control system requires significantly lower pumping power, demonstrates more isothermal control characteristics, and allows greater operational flexibility in heat load placement. As a function of JSC's Work Package responsibility for thermal management of space station equipment external to the pressurized modules, prototype development programs were initiated on the Two-Phase Thermal Bus System (TBS) and the Space Erectable Radiator System (SERS). JSC currently has several programs underway to enhance the understanding of two-phase fluid flow characteristics. The objective of one of these programs (sponsored by the Microgravity Science and Applications Division at NASA-Headquarters) is to design, fabricate, and fly a two-phase flow regime mapping experiment in the Shuttle vehicle mid-deck. Another program, sponsored by OAST, involves the testing of a two-phase thermal transport loop aboard the KC-135 reduced gravity aircraft to identify system implications of pressure drop variation as a function of the flow quality and flow regime present in a representative thermal system.

On the Stability of Collocated Controllers in the Presence or Uncertain Nonlinearities and Other Perils

NASA Technical Reports Server (NTRS)

Joshi, S. M.

1985-01-01

Robustness properties are investigated for two types of controllers for large flexible space structures, which use collocated sensors and actuators. The first type is an attitude controller which uses negative definite feedback of measured attitude and rate, while the second type is a damping enhancement controller which uses only velocity (rate) feedback. It is proved that collocated attitude controllers preserve closed loop global asymptotic stability when linear actuator/sensor dynamics satisfying certain phase conditions are present, or monotonic increasing nonlinearities are present. For velocity feedback controllers, the global asymptotic stability is proved under much weaker conditions. In particular, they have 90 phase margin and can tolerate nonlinearities belonging to the (0,infinity) sector in the actuator/sensor characteristics. The results significantly enhance the viability of both types of collocated controllers, especially when the available information about the large space structure (LSS) parameters is inadequate or inaccurate.

Thermal management of instruments on space platforms using a high capacity two-phase heat transport system

NASA Technical Reports Server (NTRS)

Ollendorf, S.; Fowle, A.; Almgren, D.

1981-01-01

A system utilizing a pumped, two-phase single component working fluid for heat exchange and transport services necessary to meet the temperature control requirements of typical orbiting instrument payloads on space platforms is described. The design characteristics of the system is presented, together with a presentation of a laboratory apparatus for demonstration of proof of concept. Results indicate that the pumped two-phase design concept can meet a wide range of thermal performance requirements with the only penalty being the requirement for a small liquid pump.

Monolithic optical integrated control circuitry for GaAs MMIC-based phased arrays

NASA Technical Reports Server (NTRS)

Bhasin, K. B.; Ponchak, G. E.; Kascak, T. J.

1985-01-01

Gallium arsenide (GaAs) monolithic microwave integrated circuits (MMIC's) show promise in phased-array antenna applications for future space communications systems. Their efficient usage will depend on the control of amplitude and phase signals for each MMIC element in the phased array and in the low-loss radiofrequency feed. For a phased array contining several MMIC elements a complex system is required to control and feed each element. The characteristics of GaAs MMIC's for 20/30-GHz phased-array systems are discussed. The optical/MMIC interface and the desired characteristics of optical integrated circuits (OIC's) for such an interface are described. Anticipated fabrication considerations for eventual full monolithic integration of optical integrated circuits with MMIC's on a GaAs substrate are presented.

Interactive computer graphics and its role in control system design of large space structures

NASA Technical Reports Server (NTRS)

Reddy, A. S. S. R.

1985-01-01

This paper attempts to show the relevance of interactive computer graphics in the design of control systems to maintain attitude and shape of large space structures to accomplish the required mission objectives. The typical phases of control system design, starting from the physical model such as modeling the dynamics, modal analysis, and control system design methodology are reviewed and the need of the interactive computer graphics is demonstrated. Typical constituent parts of large space structures such as free-free beams and free-free plates are used to demonstrate the complexity of the control system design and the effectiveness of the interactive computer graphics.

Space station group activities habitability module study

NASA Technical Reports Server (NTRS)

Nixon, David

1986-01-01

This study explores and analyzes architectural design approaches for the interior of the Space Station Habitability Module (originally defined as Habitability Module 1 in Space Station Reference Configuration Decription, JSC-19989, August 1984). In the Research Phase, architectural program and habitability design guidelines are specified. In the Schematic Design Phase, a range of alternative concepts is described and illustrated with drawings, scale-model photographs and design analysis evaluations. Recommendations are presented on the internal architectural, configuration of the Space Station Habitability Module for such functions as the wardroom, galley, exercise facility, library and station control work station. The models show full design configurations for on-orbit performance.

Langley's CSI evolutionary model: Phase O

NASA Technical Reports Server (NTRS)

Belvin, W. Keith; Elliott, Kenny B.; Horta, Lucas G.; Bailey, Jim P.; Bruner, Anne M.; Sulla, Jeffrey L.; Won, John; Ugoletti, Roberto M.

1991-01-01

A testbed for the development of Controls Structures Interaction (CSI) technology to improve space science platform pointing is described. The evolutionary nature of the testbed will permit the study of global line-of-sight pointing in phases 0 and 1, whereas, multipayload pointing systems will be studied beginning with phase 2. The design, capabilities, and typical dynamic behavior of the phase 0 version of the CSI evolutionary model (CEM) is documented for investigator both internal and external to NASA. The model description includes line-of-sight pointing measurement, testbed structure, actuators, sensors, and real time computers, as well as finite element and state space models of major components.

Growth-rate periodicity of Streptomyces levoris during space flight

NASA Technical Reports Server (NTRS)

Rogers, T. D.; Brower, M. E.; Taylor, G. R.

1977-01-01

Streptomyces levoris provides a suitable biological test system to investigate the effects of space flight on the rhythms of vegetative and spore phase characteristics of both growth-rate periodicity and culture morphology during the pre-, in-, and post-flight periods of the Apollo-Soyuz Test Project. The objectives of the American participation were to study the effects of space flight on the biorhythms of Streptomyces levoris based on a comparison of the growth-rate periodicity of the vegetative and spore phase within each culture, to examine the possible alteration of spore morphology and development by SEM, and to compare the effects of a 12-hr phase shift on the periodic growth characteristics of this microorganism in cultures which were exchanged during the joint activities of the space flight. No uniform differences in the biorhythm of Streptomyces levoris during space flight were observed. It appears that the single most variable factor related to the experiment was the lack of temperature control for the space-flight specimens.

Fluid Phase Separation (FPS) experiment for flight on a space shuttle Get Away Special (GAS) canister

NASA Technical Reports Server (NTRS)

Peters, Bruce; Wingo, Dennis; Bower, Mark; Amborski, Robert; Blount, Laura; Daniel, Alan; Hagood, Bob; Handley, James; Hediger, Donald; Jimmerson, Lisa

1990-01-01

The separation of fluid phases in microgravity environments is of importance to environmental control and life support systems (ECLSS) and materials processing in space. A successful fluid phase separation experiment will demonstrate a proof of concept for the separation technique and add to the knowledge base of material behavior. The phase separation experiment will contain a premixed fluid which will be exposed to a microgravity environment. After the phase separation of the compound has occurred, small samples of each of the species will be taken for analysis on the Earth. By correlating the time of separation and the temperature history of the fluid, it will be possible to characterize the process. The experiment has been integrated into space available on a manifested Get Away Special (GAS) experiment, CONCAP 2, part of the Consortium for Materials Complex Autonomous Payload (CAP) Program, scheduled for STS-42. The design and the production of a fluid phase separation experiment for rapid implementation at low cost is presented.

Fault-Tolerant Control For A Robotic Inspection System

NASA Technical Reports Server (NTRS)

Tso, Kam Sing

1995-01-01

Report describes first phase of continuing program of research on fault-tolerant control subsystem of telerobotic visual-inspection system. Goal of program to develop robotic system for remotely controlled visual inspection of structures in outer space.

Cryogenic Pressure Control Modeling for Ellipsoidal Space Tanks in Reduced Gravity

NASA Technical Reports Server (NTRS)

Hedayat, Ali; Lopez, Alfredo; Grayson, Gary D.; Chandler, Frank O.; Hastings, Leon J.

2008-01-01

A computational fluid dynamics (CFD) model is developed to simulate pressure control of an ellipsoidal-shaped liquid hydrogen tank under external heating in low gravity. Pressure control is provided by an axial jet thermodynamic vent system (TVS) centered within the vessel that injects cooler liquid into the tank, mixing the contents and reducing tank pressure. The two-phase cryogenic tank model considers liquid hydrogen in its own vapor with liquid density varying with temperature only and a fully compressible ullage. The axisymmetric model is developed using a custom version of the commercially available FLOW-3D software and simulates low gravity extrapolations of engineering checkout tests performed at Marshall Space Flight Center in 1999 in support of the Solar Thermal Upper Stage Technology Demonstrator (STUSTD) program. Model results illustrate that stable low gravity liquid-gas interfaces are maintained during all phases of the pressure control cycle. Steady and relatively smooth ullage pressurization rates are predicted. This work advances current low gravity CFD modeling capabilities for cryogenic pressure control and aids the development of a low cost CFD-based design process for space hardware.

Non-geometric fluxes, quasi-Hopf twist deformations, and nonassociative quantum mechanics

NASA Astrophysics Data System (ADS)

Mylonas, Dionysios; Schupp, Peter; Szabo, Richard J.

2014-12-01

We analyse the symmetries underlying nonassociative deformations of geometry in non-geometric R-flux compactifications which arise via T-duality from closed strings with constant geometric fluxes. Starting from the non-abelian Lie algebra of translations and Bopp shifts in phase space, together with a suitable cochain twist, we construct the quasi-Hopf algebra of symmetries that deforms the algebra of functions and the exterior differential calculus in the phase space description of nonassociative R-space. In this setting, nonassociativity is characterised by the associator 3-cocycle which controls non-coassociativity of the quasi-Hopf algebra. We use abelian 2-cocycle twists to construct maps between the dynamical nonassociative star product and a family of associative star products parametrized by constant momentum surfaces in phase space. We define a suitable integration on these nonassociative spaces and find that the usual cyclicity of associative noncommutative deformations is replaced by weaker notions of 2-cyclicity and 3-cyclicity. Using this star product quantization on phase space together with 3-cyclicity, we formulate a consistent version of nonassociative quantum mechanics, in which we calculate the expectation values of area and volume operators, and find coarse-graining of the string background due to the R-flux.

Large space telescope, phase A. Volume 3: Optical telescope assembly

NASA Technical Reports Server (NTRS)

1972-01-01

The development and characteristics of the optical telescope assembly for the Large Space Telescope are discussed. The systems considerations are based on mission-related parameters and optical equipment requirements. Information is included on: (1) structural design and analysis, (2) thermal design, (3) stabilization and control, (4) alignment, focus, and figure control, (5) electronic subsystem, and (6) scientific instrument design.

High Energy Astronomy Observatory, Mission C, Phase A. Volume 2: Preliminary analyses and conceptual design

NASA Technical Reports Server (NTRS)

1972-01-01

An analysis and conceptual design of a baseline mission and spacecraft are presented. Aspects of the HEAO-C discussed include: baseline experiments with X-ray observations of space, analysis of mission requirements, observatory design, structural analysis, thermal control, attitude sensing and control system, communication and data handling, and space shuttle launch and retrieval of HEAO-C.

Space shuttle guidance, navigation and control design equations. Volume 4: Deorbit and atmospheric operations

NASA Technical Reports Server (NTRS)

Cox, K. J.

1971-01-01

A baseline set of equations which fulfill the computation requirements for guidance, navigation, and control of the space shuttle orbiter vehicle is presented. All shuttle mission phases are covered from prelaunch through landing/rollout. The spacecraft flight mode and the aircraft flight mode are addressed. The baseline equations may be implemented in a single guidance, navigation, and control computer or may be distributed among several subsystem computers.

Design guidelines for assessing and controlling spacecraft charging effects

NASA Technical Reports Server (NTRS)

Purvis, C. K.; Garrett, H. B.; Whittlesey, A. C.; Stevens, N. J.

1984-01-01

The need for uniform criteria, or guidelines, to be used in all phases of spacecraft design is discussed. Guidelines were developed for the control of absolute and differential charging of spacecraft surfaces by the lower energy space charged particle environment. Interior charging due to higher energy particles is not considered. A guide to good design practices for assessing and controlling charging effects is presented. Uniform design practices for all space vehicles are outlined.

Design guidelines for assessing and controlling spacecraft charging effects

NASA Technical Reports Server (NTRS)

Purvis, C. K.; Garrett, H. B.; Whittlesey, A.; Stevens, N. J.

1985-01-01

The need for uniform criteria, or guidelines, to be used in all phases of spacecraft design is discussed. Guidelines were developed for the control of absolute and differential charging of spacecraft surfaces by the lower energy space charged particle environment. Interior charging due to higher energy particles is not considered. A guide to good design practices for assessing and controlling charging effects is presented. Uniform design practices for all space vehicles are outlined.

International Space Station Environmental Control and Life Support System Status: 2006 - 2007

NASA Technical Reports Server (NTRS)

Williams, David E.; Gentry, Gregory J.

2007-01-01

The International Space Station (ISS) Environmental Control and Life Support (ECLS) system includes regenerative and non-regenerative technologies that provide the basic life support functions to support the crew, while maintaining a safe and habitable shirtsleeve environment. This paper provides a summary of the U.S. ECLS system activities over the past year, covering the period of time between March 2006 and February 2007. The ISS continued permanent crew operations, with the start of Phase 3 of the ISS Assembly Sequence. Work continued on the Phase 3 pressurized elements and the continued manufacturing and testing of the regenerative ECLS equipment.

International Space Station Environmental Control and Life Support System Status: 2008 - 2009

NASA Technical Reports Server (NTRS)

Williams, David E.; Gentry, Gregory J.; Gentry, Gregory J.

2009-01-01

The International Space Station (ISS) Environmental Control and Life Support (ECLS) system includes regenerative and non-regenerative technologies that provide the basic life support functions to support the crew, while maintaining a safe and habitable shirtsleeve environment. This paper provides a summary of the U.S. ECLS system activities over the past year, covering the period of time between March 2008 and February 2009. The ISS continued permanent crew operations, with the continuation of Phase 3 of the ISS Assembly Sequence. Work continues on the last of the Phase 3 pressurized elements and the continued manufacturing and testing of the regenerative ECLS equipment.

International Space Station Environmental Control and Life Support System Status: 2005 - 2006

NASA Technical Reports Server (NTRS)

Williams, David E.; Gentry, Gregory J.

2006-01-01

The International Space Station (ISS) Environmental Control and Life Support (ECLS) system includes regenerative and non-regenerative technologies that provide the basic life support functions to support the crew, while maintaining a safe and habitable shirtsleeve environment. This paper provides a summary of the U.S. ECLS system activities over the past year, covering the period of time between March 2005 and February 2006. The ISS continued permanent crew operations, with the start of Phase 3 of the ISS Assembly Sequence. Work continued on the Phase 3 pressurized elements and the continued manufacturing and testing of the regenerative ECLS equipment.

International Space Station (ISS) Environmental Control and Life Support System Status: 2003-2004

NASA Technical Reports Server (NTRS)

Williams, David E.; Gentry, Gregory

2004-01-01

The International Space Station (ISS) Environmental Control and Life Support (ECLS) system includes regenerative and non-regenerative technologies that provide the basic life support functions to support the crew, while maintaining a safe and habitable shirtsleeve environment. This paper provides a summary of the U.S. ECLS system activities over the past year, covering the period of time between April 2003 and March 2004. The ISS continued permanent crew operations, with the start of Phase 3 of the ISS Assembly Sequence. Work continued on the Phase 3 pressurized elements and the continued manufacturing and testing of the regenerative ECLS equipment.

International Space Station Environmental Control and Life Support System Status: 2009 - 2010

NASA Technical Reports Server (NTRS)

Williams, David E.; Dake, Jason R.; Gentry, Gregory J.

2010-01-01

The International Space Station (ISS) Environmental Control and Life Support (ECLS) system includes regenerative and non -regenerative technologies that provide the basic life support functions to support the crew, while maintaining a safe and habitable shirtsleeve environment. This paper provides a summary of the U.S. ECLS system activities over the past year, covering the period of time between March 2009 and February 2010. The ISS continued permanent crew operations, with the start of Phase 3 of the ISS Assembly Sequence and an increase of the ISS crew size from three to six. Work continues on the last of the Phase 3 pressurized elements.

International Space Station Environmental Control and Life Support System Status: 2009 - 2010

NASA Technical Reports Server (NTRS)

Williams, David E.; Dake, Jason R.; Gentry, Gregory J.

2009-01-01

The International Space Station (ISS) Environmental Control and Life Support (ECLS) system includes regenerative and non-regenerative technologies that provide the basic life support functions to support the crew, while maintaining a safe and habitable shirtsleeve environment. This paper provides a summary of the U.S. ECLS system activities over the past year, covering the period of time between March 2009 and February 2010. The ISS continued permanent crew operations, with the start of Phase 3 of the ISS Assembly Sequence and an increase of the ISS crew size from three to six. Work continues on the last of the Phase 3 pressurized elements.

International Space Station Atmosphere Control and Supply, Atmosphere Revitalization, and Water Recovery and Management Subsystem - Verification for Node 1

NASA Technical Reports Server (NTRS)

Williams, David E.

2007-01-01

The International Space Station (ISS) Node 1 Environmental Control and Life Support (ECLS) System is comprised of five subsystems: Atmosphere Control and Supply (ACS), Atmosphere Revitalization (AR), Fire Detection and Suppression (FDS), Temperature and Humidity Control (THC), and Water Recovery and Management (WRM). This paper provides a summary of the nominal operation of the Node 1 ACS, AR, and WRM design and detailed Element Verification methodologies utilized during the Qualification phase for Node 1.

Autonomous Motion Learning for Intra-Vehicular Activity Space Robot

NASA Astrophysics Data System (ADS)

Watanabe, Yutaka; Yairi, Takehisa; Machida, Kazuo

Space robots will be needed in the future space missions. So far, many types of space robots have been developed, but in particular, Intra-Vehicular Activity (IVA) space robots that support human activities should be developed to reduce human-risks in space. In this paper, we study the motion learning method of an IVA space robot with the multi-link mechanism. The advantage point is that this space robot moves using reaction force of the multi-link mechanism and contact forces from the wall as space walking of an astronaut, not to use a propulsion. The control approach is determined based on a reinforcement learning with the actor-critic algorithm. We demonstrate to clear effectiveness of this approach using a 5-link space robot model by simulation. First, we simulate that a space robot learn the motion control including contact phase in two dimensional case. Next, we simulate that a space robot learn the motion control changing base attitude in three dimensional case.

Quantum trajectory phase transitions in the micromaser.

PubMed

Garrahan, Juan P; Armour, Andrew D; Lesanovsky, Igor

2011-08-01

We study the dynamics of the single-atom maser, or micromaser, by means of the recently introduced method of thermodynamics of quantum jump trajectories. We find that the dynamics of the micromaser displays multiple space-time phase transitions, i.e., phase transitions in ensembles of quantum jump trajectories. This rich dynamical phase structure becomes apparent when trajectories are classified by dynamical observables that quantify dynamical activity, such as the number of atoms that have changed state while traversing the cavity. The space-time transitions can be either first order or continuous, and are controlled not just by standard parameters of the micromaser but also by nonequilibrium "counting" fields. We discuss how the dynamical phase behavior relates to the better known stationary-state properties of the micromaser.

Adaptable Single Active Loop Thermal Control System (TCS) for Future Space Missions

NASA Technical Reports Server (NTRS)

Mudawar, Issam; Lee, Seunghyun; Hasan, Mohammad

2015-01-01

This presentation will examine the development of a thermal control system (TCS) for future space missions utilizing a single active cooling loop. The system architecture enables the TCS to be reconfigured during the various mission phases to respond, not only to varying heat load, but to heat rejection temperature as well. The system will consist of an accumulator, pump, cold plates (evaporators), condenser radiator, and compressor, in addition to control, bypass and throttling valves. For cold environments, the heat will be rejected by radiation, during which the compressor will be bypassed, reducing the system to a simple pumped loop that, depending on heat load, can operate in either a single-phase liquid mode or two-phase mode. For warmer environments, the pump will be bypassed, enabling the TCS to operate as a heat pump. This presentation will focus on recent findings concerning two-phase flow regimes, pressure drop, and heat transfer coefficient trends in the cabin and avionics micro-channel heat exchangers when using the heat pump mode. Also discussed will be practical implications of using micro-channel evaporators for the heat pump.

MMIC linear-phase and digital modulators for deep space spacecraft X-band transponder applications

NASA Technical Reports Server (NTRS)

Mysoor, Narayan R.; Ali, Fazal

1991-01-01

The design concepts, analyses, and development of GaAs monolithic microwave integrated circuit (MMIC) linear-phase and digital modulators for the next generation of space-borne communications systems are summarized. The design approach uses a compact lumped element quadrature hybrid and Metal Semiconductor Field Effect Transistors (MESFET)-varactors to provide low loss and well-controlled phase performance for deep space transponder (DST) applications. The measured results of the MESFET-diode show a capacitance range of 2:1 under reverse bias, and a Q of 38 at 10 GHz. Three cascaded sections of hybrid-coupled reflection phase shifters were modeled and simulations performed to provide an X-band (8415 +/- 50 MHz) DST phase modulator with +/- 2.5 radians of peak phase deviation. The modulator will accommodate downlink signal modulation with composite telemetry and ranging data, with a deviation linearity tolerance of +/- 8 percent and insertion loss of less than 8 +/- 0.5 dB. The MMIC digital modulator is designed to provide greater than 10 Mb/s of bi-phase modulation at X-band.

Phase 3 study of selected tether applications in space, mid-term review

NASA Technical Reports Server (NTRS)

1986-01-01

Topics addressed include: guidelines for the Space Transportation System (STS) payload deployer design; mini-orbital maneuvering vehicle (MOMV) design: shuttle tether deployer systems (STEDS); cost modeling; tethered platform analysis; fuel savings analysis; and STEDS control simulation.

Three-phase Four-leg Inverter LabVIEW FPGA Control Code

DOE Office of Scientific and Technical Information (OSTI.GOV)

In the area of power electronics control, Field Programmable Gate Arrays (FPGAs) have the capability to outperform their Digital Signal Processor (DSP) counterparts due to the FPGA’s ability to implement true parallel processing and therefore facilitate higher switching frequencies, higher control bandwidth, and/or enhanced functionality. National Instruments (NI) has developed two platforms, Compact RIO (cRIO) and Single Board RIO (sbRIO), which combine a real-time processor with an FPGA. The FPGA can be programmed with a subset of the well-known LabVIEW graphical programming language. The use of cRIO and sbRIO for power electronics control has developed over the last few yearsmore » to include control of three-phase inverters. Most three-phase inverter topologies include three switching legs. The addition of a fourth-leg to natively generate the neutral connection allows the inverter to serve single-phase loads in a microgrid or stand-alone power system and to balance the three-phase voltages in the presence of significant load imbalance. However, the control of a four-leg inverter is much more complex. In particular, instead of standard two-dimensional space vector modulation (SVM), the inverter requires three-dimensional space vector modulation (3D-SVM). The candidate software implements complete control algorithms in LabVIEW FPGA for a three-phase four-leg inverter. The software includes feedback control loops, three-dimensional space vector modulation gate-drive algorithms, advanced alarm handling capabilities, contactor control, power measurements, and debugging and tuning tools. The feedback control loops allow inverter operation in AC voltage control, AC current control, or DC bus voltage control modes based on external mode selection by a user or supervisory controller. The software includes the ability to synchronize its AC output to the grid or other voltage-source before connection. The software also includes provisions to allow inverter operation in parallel with other voltage regulating devices on the AC or DC buses. This flexibility allows the Inverter to operate as a stand-alone voltage source, connected to the grid, or in parallel with other controllable voltage sources as part of a microgrid or remote power system. In addition, as the inverter is expected to operate under severe unbalanced conditions, the software includes algorithms to accurately compute real and reactive power for each phase based on definitions provided in the IEEE Standard 1459: IEEE Standard Definitions for the Measurement of Electric Power Quantities Under Sinusoidal, Nonsinusoidal, Balanced, or Unbalanced Conditions. Finally, the software includes code to output analog signals for debugging and for tuning of control loops. The software fits on the Xilinx Virtex V LX110 FPGA embedded in the NI cRIO-9118 FPGA chassis, and with a 40 MHz base clock, supports a modulation update rate of 40 MHz, user-settable switching frequencies and synchronized control loop update rates of tens of kHz, and reference waveform generation, including Phase Lock Loop (PLL), update rate of 100 kHz.« less

A Local Condensation Analysis Representing Two-phase Annular Flow in Condenser/radiator Capillary Tubes

NASA Technical Reports Server (NTRS)

Karimi, Amir

1991-01-01

NASA's effort for the thermal environmental control of the Space Station Freedom is directed towards the design, analysis, and development of an Active Thermal Control System (ATCS). A two phase, flow through condenser/radiator concept was baselined, as a part of the ATCS, for the radiation of space station thermal load into space. The proposed condenser rejects heat through direct condensation of ATCS working fluid (ammonia) in the small diameter radiator tubes. Analysis of the condensation process and design of condenser tubes are based on the available two phase flow models for the prediction of flow regimes, heat transfer, and pressure drops. The prediction formulas use the existing empirical relationships of friction factor at gas-liquid interface. An attempt is made to study the stability of interfacial waves in two phase annular flow. The formulation is presented of a stability problem in cylindrical coordinates. The contribution of fluid viscosity, surface tension, and transverse radius of curvature to the interfacial surface is included. A solution is obtained for Kelvin-Helmholtz instability problem which can be used to determine the critical and most dangerous wavelengths for interfacial waves.

Integrated digital flight-control system for the space shuttle orbiter

NASA Technical Reports Server (NTRS)

1973-01-01

The integrated digital flight control system is presented which provides rotational and translational control of the space shuttle orbiter in all phases of flight: from launch ascent through orbit to entry and touchdown, and during powered horizontal flights. The program provides a versatile control system structure while maintaining uniform communications with other programs, sensors, and control effectors by using an executive routine/functional subroutine format. The program reads all external variables at a single point, copies them into its dedicated storage, and then calls the required subroutines in the proper sequence. As a result, the flight control program is largely independent of other programs in the GN&C computer complex and is equally insensitive to the characteristics of the processor configuration. The integrated structure of the control system and the DFCS executive routine which embodies that structure are described along with the input and output. The specific estimation and control algorithms used in the various mission phases are given.

Space shuttle main engine definition (phase B). Volume 2: Avionics. [for space shuttle

NASA Technical Reports Server (NTRS)

1971-01-01

The advent of the space shuttle engine with its requirements for high specific impulse, long life, and low cost have dictated a combustion cycle and a closed loop control system to allow the engine components to run close to operating limits. These performance requirements, combined with the necessity for low operational costs, have placed new demands on rocket engine control, system checkout, and diagnosis technology. Based on considerations of precision environment, and compatibility with vehicle interface commands, an electronic control, makes available many functions that logically provide the information required for engine system checkout and diagnosis.

Optimal control problems with mixed control-phase variable equality and inequality constraints

NASA Technical Reports Server (NTRS)

Makowski, K.; Neustad, L. W.

1974-01-01

In this paper, necessary conditions are obtained for optimal control problems containing equality constraints defined in terms of functions of the control and phase variables. The control system is assumed to be characterized by an ordinary differential equation, and more conventional constraints, including phase inequality constraints, are also assumed to be present. Because the first-mentioned equality constraint must be satisfied for all t (the independent variable of the differential equation) belonging to an arbitrary (prescribed) measurable set, this problem gives rise to infinite-dimensional equality constraints. To obtain the necessary conditions, which are in the form of a maximum principle, an implicit-function-type theorem in Banach spaces is derived.

Phase A conceptual design study of the Atmospheric, Magnetospheric and Plasmas in Space (AMPS) payload

NASA Technical Reports Server (NTRS)

1974-01-01

The 12 month Phase A Conceptual Design Study of the Atmospheric, Magnetospheric and Plasmas in Space (AMPS) payload performed within the Program Development Directorate of the Marshall Space Flight Center is presented. The AMPS payload makes use of the Spacelab pressurized module and pallet, is launched by the space shuttle, and will have initial flight durations of 7 days. Scientific instruments including particle accelerators, high power transmitters, optical instruments, and chemical release devices are mounted externally on the Spacelab pallet and are controlled by the experimenters from within the pressurized module. The capability of real-time scientist interaction on-orbit with the experiment is a major characteristic of AMPS.

Thermal control system for Space Station Freedom photovoltaic power module

NASA Technical Reports Server (NTRS)

Hacha, Thomas H.; Howard, Laura

1994-01-01

The electric power for Space Station Freedom (SSF) is generated by the solar arrays of the photovoltaic power modules (PVM's) and conditioned, controlled, and distributed by a power management and distribution system. The PVM's are located outboard of the alpha gimbals of SSF. A single-phase thermal control system is being developed to provide thermal control of PVM electrical equipment and energy storage batteries. This system uses ammonia as the coolant and a direct-flow deployable radiator. The description and development status of the PVM thermal control system is presented.

Thermal control system for Space Station Freedom photovoltaic power module

NASA Technical Reports Server (NTRS)

Hacha, Thomas H.; Howard, Laura S.

1992-01-01

The electric power for Space Station Freedom (SSF) is generated by the solar arrays of the photovoltaic power modules (PVM's) and conditioned, controlled, and distributed by a power management and distribution system. The PVM's are located outboard of the alpha gimbals of SSF. A single-phase thermal control system is being developed to provide thermal control of PVM electrical equipment and energy storage batteries. This system uses ammonia as the coolant and a direct-flow deployable radiator. This paper presents the description and development status of the PVM thermal control system.

Optical authentication based on moiré effect of nonlinear gratings in phase space

NASA Astrophysics Data System (ADS)

Liao, Meihua; He, Wenqi; Wu, Jiachen; Lu, Dajiang; Liu, Xiaoli; Peng, Xiang

2015-12-01

An optical authentication scheme based on the moiré effect of nonlinear gratings in phase space is proposed. According to the phase function relationship of the moiré effect in phase space, an arbitrary authentication image can be encoded into two nonlinear gratings which serve as the authentication lock (AL) and the authentication key (AK). The AL is stored in the authentication system while the AK is assigned to the authorized user. The authentication procedure can be performed using an optoelectronic approach, while the design process is accomplished by a digital approach. Furthermore, this optical authentication scheme can be extended for multiple users with different security levels. The proposed scheme can not only verify the legality of a user identity, but can also discriminate and control the security levels of legal users. Theoretical analysis and simulation experiments are provided to verify the feasibility and effectiveness of the proposed scheme.

Automated Design of Multiphase Space Missions Using Hybrid Optimal Control

ERIC Educational Resources Information Center

Chilan, Christian Miguel

2009-01-01

A modern space mission is assembled from multiple phases or events such as impulsive maneuvers, coast arcs, thrust arcs and planetary flybys. Traditionally, a mission planner would resort to intuition and experience to develop a sequence of events for the multiphase mission and to find the space trajectory that minimizes propellant use by solving…

Massive Multi-Agent Systems Control

NASA Technical Reports Server (NTRS)

Campagne, Jean-Charles; Gardon, Alain; Collomb, Etienne; Nishida, Toyoaki

2004-01-01

In order to build massive multi-agent systems, considered as complex and dynamic systems, one needs a method to analyze and control the system. We suggest an approach using morphology to represent and control the state of large organizations composed of a great number of light software agents. Morphology is understood as representing the state of the multi-agent system as shapes in an abstract geometrical space, this notion is close to the notion of phase space in physics.

NASA Flight Planning Branch Space Shuttle Lessons Learned

NASA Technical Reports Server (NTRS)

Clevenger, Jennifer D.; Bristol, Douglas J.; Whitney, Gregory R.; Blanton, Mark R.; Reynolds, F. Fisher, III

2011-01-01

Planning products and procedures that allowed the mission Flight Control Teams and the Astronaut crews to plan, train and fly every Space Shuttle mission were developed by the Flight Planning Branch at the NASA Johnson Space Center in Houston, Texas. As the Space Shuttle Program came to a close, lessons learned were collected from each phase of the successful execution of these Space Shuttle missions. Specific examples of how roles and responsibilities of console positions that develop the crew and vehicle attitude timelines have been analyzed and will be discussed. Additionally, the relationships and procedural hurdles experienced through international collaboration have molded operations. These facets will be explored and related to current and future operations with the International Space Station and future vehicles. Along with these important aspects, the evolution of technology and continual improvement of data transfer tools between the Space Shuttle and ground team has also defined specific lessons used in improving the control team s effectiveness. Methodologies to communicate and transmit messages, images, and files from the Mission Control Center to the Orbiter evolved over several years. These lessons were vital in shaping the effectiveness of safe and successful mission planning and have been applied to current mission planning work in addition to being incorporated into future space flight planning. The critical lessons from all aspects of previous plan, train, and fly phases of Space Shuttle flight missions are not only documented in this paper, but are also discussed regarding how they pertain to changes in process and consideration for future space flight planning.

Dynamic modeling and Super-Twisting Sliding Mode Control for Tethered Space Robot

NASA Astrophysics Data System (ADS)

Zhao, Yakun; Huang, Panfeng; Zhang, Fan

2018-02-01

Recent years, tethered space capturing systems have been considered as one of the most promising solutions for active space debris removal due to the increasing threat of space debris to spacecraft and astronauts. In this paper, one of the tethered space capturing systems, Tethered Space Robot (TSR), is investigated. TSR includes a space platform, a space tether, and a gripper as the terminal device. Based on the assumptions that the platform and the gripper are point masses and the tether is rigid, inextensible and remaining straight, the dynamic model of TSR is presented, in which the disturbances from space environment is considered. According to the previous study, the in-plane and out-of-plane angles of the tether oscillate periodically although the tether is released to the desired length. A super-twisting adaptive sliding mode control scheme is designed for TSR to eliminate the vibration of the tether to assure a successful capture in station-keeping phase. Both uncontrolled and controlled situations are simulated. The simulation results show that the proposed controller is effective. Additionally, after comparing with normal sliding mode control algorithm, it is verified that the proposed control scheme can avoid the chattering of normal sliding mode control and is robust for unknown boundary perturbations.

Converging Redundant Sensor Network Information for Improved Building Control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dale Tiller; D. Phil; Gregor Henze

2007-09-30

This project investigated the development and application of sensor networks to enhance building energy management and security. Commercial, industrial and residential buildings often incorporate systems used to determine occupancy, but current sensor technology and control algorithms limit the effectiveness of these systems. For example, most of these systems rely on single monitoring points to detect occupancy, when more than one monitoring point could improve system performance. Phase I of the project focused on instrumentation and data collection. During the initial project phase, a new occupancy detection system was developed, commissioned and installed in a sample of private offices and open-planmore » office workstations. Data acquisition systems were developed and deployed to collect data on space occupancy profiles. Phase II of the project demonstrated that a network of several sensors provides a more accurate measure of occupancy than is possible using systems based on single monitoring points. This phase also established that analysis algorithms could be applied to the sensor network data stream to improve the accuracy of system performance in energy management and security applications. In Phase III of the project, the sensor network from Phase I was complemented by a control strategy developed based on the results from the first two project phases: this controller was implemented in a small sample of work areas, and applied to lighting control. Two additional technologies were developed in the course of completing the project. A prototype web-based display that portrays the current status of each detector in a sensor network monitoring building occupancy was designed and implemented. A new capability that enables occupancy sensors in a sensor network to dynamically set the 'time delay' interval based on ongoing occupant behavior in the space was also designed and implemented.« less

Mechanism controller system for the optical spectroscopic and infrared remote imaging system instrument on board the Rosetta space mission

NASA Astrophysics Data System (ADS)

Castro Marín, J. M.; Brown, V. J. G.; López Jiménez, A. C.; Rodríguez Gómez, J.; Rodrigo, R.

2001-05-01

The optical, spectroscopic infrared remote imaging system (OSIRIS) is an instrument carried on board the European Space Agency spacecraft Rosetta that will be launched in January 2003 to study in situ the comet Wirtanen. The electronic design of the mechanism controller board (MCB) system of the two OSIRIS optical cameras, the narrow angle camera, and the wide angle camera, is described here. The system is comprised of two boards mounted on an aluminum frame as part of an electronics box that contains the power supply and the digital processor unit of the instrument. The mechanisms controlled by the MCB for each camera are the front door assembly and a filter wheel assembly. The front door assembly for each camera is driven by a four phase, permanent magnet stepper motor. Each filter wheel assembly consists of two, eight filter wheels. Each wheel is driven by a four phase, variable reluctance stepper motor. Each motor, for all the assemblies, also contains a redundant set of four stator phase windings that can be energized separately or in parallel with the main windings. All stepper motors are driven in both directions using the full step unipolar mode of operation. The MCB also performs general housekeeping data acquisition of the OSIRIS instrument, i.e., mechanism position encoders and temperature measurements. The electronic design application used is quite new due to use of a field programmable gate array electronic devices that avoid the use of the now traditional system controlled by microcontrollers and software. Electrical tests of the engineering model have been performed successfully and the system is ready for space qualification after environmental testing. This system may be of interest to institutions involved in future space experiments with similar needs for mechanisms control.

Microgravity experiments of nano-satellite docking mechanism for final rendezvous approach and docking phase

NASA Astrophysics Data System (ADS)

Ui, Kyoichi; Matunaga, Saburo; Satori, Shin; Ishikawa, Tomohiro

2005-09-01

Laboratory for Space Systems (LSS), Tokyo Institute of Technology (Tokyo Tech) conducted three-dimensional microgravity environment experiments about a docking mechanism for mothership-daughtership (MS-DS) nano-satellite using the facility of Japan Micro Gravity Center (JAMIC) with Hokkaido Institute of Technology (HIT). LSS has studied and developed a docking mechanism for MS-DS nano-satellite system in final rendezvous approach and docking phase since 2000. Consideration of the docking mechanism is to mate a nano-satellite stably while remaining control error of relative velocity and attitude because it is difficult for nano-satellite to have complicated attitude control and mating systems. Objective of the experiments is to verify fundamental grasping function based on our proposed docking methodology. The proposed docking sequence is divided between approach/grasping phase and guiding phase. In the approach/grasping phase, the docking mechanism grasps the nano-satellite even though the nano-satellite has relative position and attitude control errors as well as relative velocity in a docking space. In the guiding function, the docking mechanism guides the nano-satellite to a docking port while adjusting its attitude in order to transfer electrical power and fuel to the nano-satellite. In the paper, we describe the experimental system including the docking mechanism, control system, the daughtership system and the release mechanism, and describe results of microgravity experiments in JAMIC.

Uniaxial strain control of spin-polarization in multicomponent nematic order of BaFe 2As 2

DOE PAGES

Kissikov, T.; Sarkar, R.; Lawson, M.; ...

2018-03-13

The iron-based high temperature superconductors exhibit a rich phase diagram reflecting a complex interplay between spin, lattice, and orbital degrees of freedom. The nematic state observed in these compounds epitomizes this complexity, by entangling a real-space anisotropy in the spin fluctuation spectrum with ferro-orbital order and an orthorhombic lattice distortion. A subtle and less-explored facet of the interplay between these degrees of freedom arises from the sizable spin-orbit coupling present in these systems, which translates anisotropies in real space into anisotropies in spin space. We present nuclear magnetic resonance studies, which reveal that the magnetic fluctuation spectrum in the paramagneticmore » phase of BaFe 2As 2 acquires an anisotropic response in spin-space upon application of a tetragonal symmetry-breaking strain field. Lastly, our results unveil an internal spin structure of the nematic order parameter, indicating that electronic nematic materials may offer a route to magneto-mechanical control.« less

Cocaine-Induced Changes in Low-Dimensional Attractors of Local Field Potentials in Optogenetic Mice

PubMed Central

Oprisan, Sorinel A.; Imperatore, Julia; Helms, Jessica; Tompa, Tamas; Lavin, Antonieta

2018-01-01

Optogenetically evoked local field potential (LFP) recorded from the medial prefrontal cortex (mPFC) of mice during basal conditions and following a systemic cocaine administration were analyzed. Blue light stimuli were delivered to mPFC through a fiber optic every 2 s and each trial was repeated 100 times. As in the previous study, we used a surrogate data method to check that nonlinearity was present in the experimental LFPs and only used the last 1.5 s of steady activity to measure the LFPs phase resetting induced by the brief 10 ms light stimulus. We found that the steady dynamics of the mPFC in response to light stimuli could be reconstructed in a three-dimensional phase space with topologically similar “8”-shaped attractors across different animals. Therefore, cocaine did not change the complexity of the recorded nonlinear data compared to the control case. The phase space of the reconstructed attractor is determined by the LFP time series and its temporally shifted versions by a multiple of some lag time. We also compared the change in the attractor shape between cocaine-injected and control using (1) dendrogram clustering and (2) Frechet distance. We found about 20% overlap between control and cocaine trials when classified using dendrogram method, which suggest that it may be possible to describe mathematically both data sets with the same model and slightly different model parameters. We also found that the lag times are about three times shorter for cocaine trials compared to control. As a result, although the phase space trajectories for control and cocaine may look similar, their dynamics is significantly different. PMID:29445337

A new balancing three level three dimensional space vector modulation strategy for three level neutral point clamped four leg inverter based shunt active power filter controlling by nonlinear back stepping controllers.

PubMed

Chebabhi, Ali; Fellah, Mohammed Karim; Kessal, Abdelhalim; Benkhoris, Mohamed F

2016-07-01

In this paper is proposed a new balancing three-level three dimensional space vector modulation (B3L-3DSVM) strategy which uses a redundant voltage vectors to realize precise control and high-performance for a three phase three-level four-leg neutral point clamped (NPC) inverter based Shunt Active Power Filter (SAPF) for eliminate the source currents harmonics, reduce the magnitude of neutral wire current (eliminate the zero-sequence current produced by single-phase nonlinear loads), and to compensate the reactive power in the three-phase four-wire electrical networks. This strategy is proposed in order to gate switching pulses generation, dc bus voltage capacitors balancing (conserve equal voltage of the two dc bus capacitors), and to switching frequency reduced and fixed of inverter switches in same times. A Nonlinear Back Stepping Controllers (NBSC) are used for regulated the dc bus voltage capacitors and the SAPF injected currents to robustness, stabilizing the system and to improve the response and to eliminate the overshoot and undershoot of traditional PI (Proportional-Integral). Conventional three-level three dimensional space vector modulation (C3L-3DSVM) and B3L-3DSVM are calculated and compared in terms of error between the two dc bus voltage capacitors, SAPF output voltages and THDv, THDi of source currents, magnitude of source neutral wire current, and the reactive power compensation under unbalanced single phase nonlinear loads. The success, robustness, and the effectiveness of the proposed control strategies are demonstrated through simulation using Sim Power Systems and S-Function of MATLAB/SIMULINK. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

CMIF ECLS system test findings

NASA Technical Reports Server (NTRS)

Schunk, Richard G.; Carrasquillo, Robyn L.; Ogle, Kathyrn Y.; Wieland, Paul O.; Bagdigian, Robert M.

1989-01-01

During 1987 three Space Station integrated Environmental Control and Life Support System (ECLSS) tests were conducted at the Marshall Space Flight Center (MSFC) Core Module Integration Facility (CMIF) as part of the MSFC ECLSS Phase II test program. The three tests ranged in duration from 50 to 150 hours and were conducted inside of the CMIF module simulator. The Phase II partial integrated system test configuration consisted of four regenerative air revitalization subsystems and one regenerative water reclamation subsystem. This paper contains a discussion of results and lessons learned from the Phase II test program. The design of the Phase II test configuration and improvements made throughout the program are detailed. Future plans for the MSFC CMIF test program are provided, including an overview of planned improvements for the Phase III program.

Analysis and experimental demonstration of conformal adaptive phase-locked fiber array for laser communications and beam projection applications

NASA Astrophysics Data System (ADS)

Liu, Ling

The primary goal of this research is the analysis, development, and experimental demonstration of an adaptive phase-locked fiber array system for free-space optical communications and laser beam projection applications. To our knowledge, the developed adaptive phase-locked system composed of three fiber collimators (subapertures) with tip-tilt wavefront phase control at each subaperture represents the first reported fiber array system that implements both phase-locking control and adaptive wavefront tip-tilt control capabilities. This research has also resulted in the following innovations: (a) The first experimental demonstration of a phase-locked fiber array with tip-tilt wave-front aberration compensation at each fiber collimator; (b) Development and demonstration of the fastest currently reported stochastic parallel gradient descent (SPGD) system capable of operation at 180,000 iterations per second; (c) The first experimental demonstration of a laser communication link based on a phase-locked fiber array; (d) The first successful experimental demonstration of turbulence and jitter-induced phase distortion compensation in a phase-locked fiber array optical system; (e) The first demonstration of laser beam projection onto an extended target with a randomly rough surface using a conformal adaptive fiber array system. Fiber array optical systems, the subject of this study, can overcome some of the draw-backs of conventional monolithic large-aperture transmitter/receiver optical systems that are usually heavy, bulky, and expensive. The primary experimental challenges in the development of the adaptive phased-locked fiber-array included precise (<5 microrad) alignment of the fiber collimators and development of fast (100kHz-class) phase-locking and wavefront tip-tilt control systems. The precise alignment of the fiber collimator array is achieved through a specially developed initial coarse alignment tool based on high precision piezoelectric picomotors and a dynamic fine alignment mechanism implemented with specially designed and manufactured piezoelectric fiber positioners. Phase-locking of the fiber collimators is performed by controlling the phases of the output beams (beamlets) using integrated polarization-maintaining (PM) fiber-coupled LiNbO3 phase shifters. The developed phase-locking controllers are based on either the SPGD algorithm or the multi-dithering technique. Subaperture wavefront phase tip-tilt control is realized using piezoelectric fiber positioners that are controlled using a computer-based SPGD controller. Both coherent (phase-locked) and incoherent beam combining in the fiber array system are analyzed theoretically and experimentally. Two special fiber-based beam-combining testbeds have been built to demonstrate the technical feasibility of phase-locking compensation prior to free-space operation. In addition, the reciprocity of counter-propagating beams in a phase-locked fiber array system has been investigated. Coherent beam combining in a phase-locking system with wavefront phase tip-tilt compensation at each subaperture is successfully demonstrated when laboratory-simulated turbulence and wavefront jitters are present in the propagation path of the beamlets. In addition, coherent beam combining with a non-cooperative extended target in the control loop is successfully demonstrated.

Design of geometric phase measurement in EAST Tokamak

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lan, T.; Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031; Liu, H. Q., E-mail: hqliu@ipp.ac.cn

2016-07-15

The optimum scheme for geometric phase measurement in EAST Tokamak is proposed in this paper. The theoretical values of geometric phase for the probe beams of EAST Polarimeter-Interferometer (POINT) system are calculated by path integration in parameter space. Meanwhile, the influences of some controllable parameters on geometric phase are evaluated. The feasibility and challenge of distinguishing geometric effect in the POINT signal are also assessed in detail.

Thermal System Upgrade of the Space Environment Simulation Test Chamber

NASA Technical Reports Server (NTRS)

Desai, Ashok B.

1997-01-01

The paper deals with the refurbishing and upgrade of the thermal system for the existing thermal vacuum test facility, the Space Environment Simulator, at NASA's Goddard Space Flight Center. The chamber is the largest such facility at the center. This upgrade is the third phase of the long range upgrade of the chamber that has been underway for last few years. The first phase dealt with its vacuum system, the second phase involved the GHe subsystem. The paper describes the considerations of design philosophy options for the thermal system; approaches taken and methodology applied, in the evaluation of the remaining "life" in the chamber shrouds and related equipment by conducting special tests and studies; feasibility and extent of automation, using computer interfaces and Programmable Logic Controllers in the control system and finally, matching the old components to the new ones into an integrated, highly reliable and cost effective thermal system for the facility. This is a multi-year project just started and the paper deals mainly with the plans and approaches to implement the project successfully within schedule and costs.

Procedures adopted by orthodontists for space closure and anchorage control.

PubMed

Monini, André da Costa; Gandini Júnior, Luiz Gonzaga; dos Santos-Pinto, Ary; Maia, Luiz Guilherme Martins; Rodrigues, Willian Caetano

2013-01-01

The aim of this study was to identify the procedures adopted by Brazilian orthodontists in the following situations: extraction space closure, anchorage control in case of necessary anchorage for group A and frequency of skeletal anchorage use, especially in the upper jaw. A questionnaire was sent to the e-mail address of all dentists registered in the Brazilian Federal Council of Dentistry. The results showed that most Brazilian orthodontists usually perform extraction space closure by means of sliding mechanics. The use of palatal bar, inclusion of second molars in the archwire and space closure performed in two phases are the most used techniques for anchorage control in the upper jaw. The skeletal anchorage is referenced by 36.5% of specialists as a routine practice for the upper arch anchorage. There is a wide variety of procedures adopted by Brazilian orthodontists for orthodontic space closure and anchorage control.

Contamination Control and Hardware Processing Solutions at Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

Burns, DeWitt H.; Hampton, Tammy; Huey, LaQuieta; Mitchell, Mark; Norwood, Joey; Lowrey, Nikki

2012-01-01

The Contamination Control Team of Marshall Space Flight Center's Materials and Processes Laboratory supports many Programs/ Projects that design, manufacture, and test a wide range of hardware types that are sensitive to contamination and foreign object damage (FOD). Examples where contamination/FOD concerns arise include sensitive structural bondline failure, critical orifice blockage, seal leakage, and reactive fluid compatibility (liquid oxygen, hydrazine) as well as performance degradation of sensitive instruments or spacecraft surfaces such as optical elements and thermal control systems. During the design phase, determination of the sensitivity of a hardware system to different types or levels of contamination/FOD is essential. A contamination control and FOD control plan must then be developed and implemented through all phases of ground processing, and, sometimes, on-orbit use, recovery, and refurbishment. Implementation of proper controls prevents cost and schedule impacts due to hardware damage or rework and helps assure mission success. Current capabilities are being used to support recent and on-going activities for multiple Mission Directorates / Programs such as International Space Station (ISS), James Webb Space Telescope (JWST), Space Launch System (SLS) elements (tanks, engines, booster), etc. The team also advances Green Technology initiatives and addresses materials obsolescence issues for NASA and external customers, most notably in the area of solvent replacement (e.g. aqueous cleaners containing hexavalent chrome, ozone depleting chemicals (CFC s and HCFC's), suspect carcinogens). The team evaluates new surface cleanliness inspection and cleaning technologies (e.g. plasma cleaning), and maintains databases for processing support materials as well as outgassing and optical compatibility test results for spaceflight environments.

Method for Controlling Space Transportation System Life Cycle Costs

NASA Technical Reports Server (NTRS)

McCleskey, Carey M.; Bartine, David E.

2006-01-01

A structured, disciplined methodology is required to control major cost-influencing metrics of space transportation systems during design and continuing through the test and operations phases. This paper proposes controlling key space system design metrics that specifically influence life cycle costs. These are inclusive of flight and ground operations, test, and manufacturing and infrastructure. The proposed technique builds on today's configuration and mass properties control techniques and takes on all the characteristics of a classical control system. While the paper does not lay out a complete math model, key elements of the proposed methodology are explored and explained with both historical and contemporary examples. Finally, the paper encourages modular design approaches and technology investments compatible with the proposed method.

International Space Station Environmental Control and Life Support System: Verification for the Pressurized Mating Adapters

NASA Technical Reports Server (NTRS)

Williams, David E.

2007-01-01

The International Space Station (ISS) Pressurized Mating Adapters (PMAs) Environmental Control and Life Support (ECLS) System is comprised of three subsystems: Atmosphere Control and Supply (ACS), Temperature and Humidity Control (THC), and Water Recovery and Management (WRM). PMA 1 and PMA 2 flew to ISS on Flight 2A and PMA 3 flew to ISS on Flight 3A. This paper provides a summary of the PMAs ECLS design and the detailed Element Verification methodologies utilized during the Qualification phase for the PMAs.

International Space Station Temperature and Humidity Control Subsystem Verification for Node 1

NASA Technical Reports Server (NTRS)

Williams, David E.

2007-01-01

The International Space Station (ISS) Node 1 Environmental Control and Life Support (ECLS) System is comprised of five subsystems: Atmosphere Control and Supply (ACS), Atmosphere Revitalization (AR), Fire Detection and Suppression (FDS), Temperature and Humidity Control (THC), and Water Recovery and Management (WRM). This paper provides a summary of the nominal operation of the Node 1 THC subsystem design. The paper will also provide a discussion of the detailed Element Verification methodologies for nominal operation of the Node 1 THC subsystem operations utilized during the Qualification phase.

Automated power distribution system hardware. [for space station power supplies

NASA Technical Reports Server (NTRS)

Anderson, Paul M.; Martin, James A.; Thomason, Cindy

1989-01-01

An automated power distribution system testbed for the space station common modules has been developed. It incorporates automated control and monitoring of a utility-type power system. Automated power system switchgear, control and sensor hardware requirements, hardware design, test results, and potential applications are discussed. The system is designed so that the automated control and monitoring of the power system is compatible with both a 208-V, 20-kHz single-phase AC system and a high-voltage (120 to 150 V) DC system.

How the Station will operate. [operation, management, and maintenance in space

NASA Technical Reports Server (NTRS)

Cox, John T.

1988-01-01

Aspects of the upcoming operational phase of the Space Station (SS) are examined. What the crew members will do with their time in their specialized roles is addressed. SS maintenance and servicing and the interaction of the SS Control Center with Johnson Space Center is discussed. The planning of payload operations and strategic planning for the SS are examined.

Microwave Imaging Radar Reflectometer System Utilizing Digital Beam Forming

NASA Astrophysics Data System (ADS)

Hu, Fengqi; Li, Meijiao; Domier, Calvin W.; Liu, Xiaoguang; Luhmann, Neville C., Jr.

2016-10-01

Microwave Imaging Reflectometry is a radar-like technique developed to measure the electron density fluctuations in fusion plasmas. Phased Antenna Arrays can serve as electronically controlled ``lenses'' that can generate the required wavefronts by phase shifting and amplitude scaling, which is being realized in the digital domain with higher flexibility and faster processing speed. In the transmitter, the resolution of the phase control is 1.4 degrees and the amplitude control is 0.5 dB/ step. A V-band double-sided, printed bow tie antenna which exhibits 49% bandwidth (46 - 76 GHz) is employed. The antenna is fed by a microstrip transmission line for easy impedance matching. The simple structure and the small antenna are suitable for low cost fabrication, easy circuit integration, and phased antenna array multi-frequency applications. In the receiver part, a sub-array of 32 channels with 200 mil spacing is used to collect the scattered reflected signal from one unit spot on the plasma cutoff surface. Pre-amplification is used to control the noise level of the system and wire bondable components are used to accommodate the small spacing between each channel. After down converting, base band signals are digitized and processed in an FPGA module. U.S. Department of Energy Grant No. DE-FG02-99ER54531.

A generic multi-flex-body dynamics, controls simulation tool for space station

NASA Technical Reports Server (NTRS)

London, Ken W.; Lee, John F.; Singh, Ramen P.; Schubele, Buddy

1991-01-01

An order (n) multiflex body Space Station simulation tool is introduced. The flex multibody modeling is generic enough to model all phases of Space Station from build up through to Assembly Complete configuration and beyond. Multibody subsystems such as the Mobile Servicing System (MSS) undergoing a prescribed translation and rotation are also allowed. The software includes aerodynamic, gravity gradient, and magnetic field models. User defined controllers can be discrete or continuous. Extensive preprocessing of 'body by body' NASTRAN flex data is built in. A significant aspect, too, is the integrated controls design capability which includes model reduction and analytic linearization.

A 2-to-48-MHz Phase-Locked Loop

NASA Technical Reports Server (NTRS)

Koudelka, Robert D.

2004-01-01

A 2-to-48-MHz phase-locked loop (PLL), developed for the U.S. space program, meets or exceeds all space shuttle clock electrical interface requirements by taking as its reference a 2-to-48-MHz clock signal and outputting a phaselocked clock signal set at the same frequency as the reference clock with transistor- transistor logic (TTL) voltage levels. Because it is more adaptable than other PLLs, the new PLL can be used in industries that employ signaling devices and as a tool in future space missions. A conventional PLL consists of a phase/frequency detector, loop filter, and voltage-controlled oscillator in which each component exists individually and is integrated into a single device. PLL components phase-lock to a single frequency or to a narrow bandwidth of frequencies. It is this design, however, that prohibits them from maintaining phase lock to a dynamically changing reference clock when a large bandwidth is required a deficiency the new PLL overcomes. Since most PLL components require their voltage-controlled oscillators to operate at greater than 2-MHz frequencies, conventional PLLs often cannot achieve the low-frequency phase lock allowed by the new PLL. The 2-to-48-MHz PLL is built on a wire-wrap board with pins wired to three position jumpers; this makes changing configurations easy. It responds to variations in voltage-controlled oscillator (VCO) ranges, duty cycle, signal-to-noise ratio (SNR), amplitude, and jitter, exceeding design specifications. A consensus state machine, implemented in a VCO range detector which assures the PLL continues to operate in the correct range, is the primary control state machine for the 2-to-48-MHz PLL circuit. By using seven overlapping frequency ranges with hysteresis, the PLL output sets the resulting phase-locked clock signal at a frequency that agrees with the reference clock with TTL voltage levels. As a space-shuttle tool, the new PLL circuit takes the noisy, degraded reference clock signals as input and outputs phase-locked clock signals of the same frequency but with a corrected wave shape. Since its configuration circuit can be easily changed, the new PLL can do the following: readily respond to variations in VCO ranges, duty cycle, SNR, amplitude, and jitter; continuously operate in the correct VCO range because of its consensus state machine; and use its range detector implements to overlap seven frequency ranges with hysteresis, thus giving the current design a flexibility that exceeds anything available at the time of this development. These features will benefit any industry in which safe and timely clock signals are vital to operation.

MSFC Sortie Laboratory Environmental Control System (ECS) phase B design study results

NASA Technical Reports Server (NTRS)

Ignatonis, A. J.; Mitchell, K. L.

1974-01-01

Phase B effort of the Sortie Lab program has concluded. Results of that effort are presented which pertain to the definitions of the environmental control system (ECS). Numerous design studies were performed in Phase B to investigate system feasibility, complexity, weight, and cost. The results and methods employed for these design studies are included. An autonomous Sortie Lab ECS was developed which utilizes a deployed space radiator. Total system weight was projected to be 1814.4 kg including the radiator and fluids. ECS power requirements were estimated at 950 watts.

Observation and Uses of Position-Space Bloch Oscillations in an Ultracold Gas.

PubMed

Geiger, Zachary A; Fujiwara, Kurt M; Singh, Kevin; Senaratne, Ruwan; Rajagopal, Shankari V; Lipatov, Mikhail; Shimasaki, Toshihiko; Driben, Rodislav; Konotop, Vladimir V; Meier, Torsten; Weld, David M

2018-05-25

We report the observation and characterization of position-space Bloch oscillations using cold atoms in a tilted optical lattice. While momentum-space Bloch oscillations are a common feature of optical lattice experiments, the real-space center-of-mass dynamics are typically unresolvable. In a regime of rapid tunneling and low force, we observe real-space Bloch oscillation amplitudes of hundreds of lattice sites, in both ground and excited bands. We demonstrate two unique capabilities enabled by tracking of Bloch dynamics in position space: measurement of the full position-momentum phase-space evolution during a Bloch cycle, and direct imaging of the lattice band structure. These techniques, along with the ability to exert long-distance coherent control of quantum gases without modulation, may open up new possibilities for quantum control and metrology.

Study of liquid crystal space groups using controlled tilting with cryogenic transmission electron microscopy.

PubMed

Sagalowicz, Laurent; Acquistapace, Simone; Watzke, Heribert J; Michel, Martin

2007-11-20

We developed a method that enables differentiation between liquid crystalline-phase particles corresponding to different space groups. It consists of controlled tilting of the specimen to observe different orientations of the same particle using cryogenic transmission electron microscopy. This leads to the visualization of lattice planes (or reflections) that are present for a given structure and absent for the other one(s) and that give information on liquid crystalline structures and their space groups. In particular, we show that we can unambiguously distinguish among particles having the inverted micellar cubic (space group Fd(3)m, 227), the inverted bicontinuous gyroid (space group Ia(3)d, 230), the inverted bicontinuous diamond (space group Pn(3)m, 224), and the inverted bicontinuous primitive cubic structure (space group Im(3)m, 229).

Observation and Uses of Position-Space Bloch Oscillations in an Ultracold Gas

NASA Astrophysics Data System (ADS)

Geiger, Zachary A.; Fujiwara, Kurt M.; Singh, Kevin; Senaratne, Ruwan; Rajagopal, Shankari V.; Lipatov, Mikhail; Shimasaki, Toshihiko; Driben, Rodislav; Konotop, Vladimir V.; Meier, Torsten; Weld, David M.

2018-05-01

We report the observation and characterization of position-space Bloch oscillations using cold atoms in a tilted optical lattice. While momentum-space Bloch oscillations are a common feature of optical lattice experiments, the real-space center-of-mass dynamics are typically unresolvable. In a regime of rapid tunneling and low force, we observe real-space Bloch oscillation amplitudes of hundreds of lattice sites, in both ground and excited bands. We demonstrate two unique capabilities enabled by tracking of Bloch dynamics in position space: measurement of the full position-momentum phase-space evolution during a Bloch cycle, and direct imaging of the lattice band structure. These techniques, along with the ability to exert long-distance coherent control of quantum gases without modulation, may open up new possibilities for quantum control and metrology.

Polarization-Independent Silicon Metadevices for Efficient Optical Wavefront Control.

PubMed

Chong, Katie E; Staude, Isabelle; James, Anthony; Dominguez, Jason; Liu, Sheng; Campione, Salvatore; Subramania, Ganapathi S; Luk, Ting S; Decker, Manuel; Neshev, Dragomir N; Brener, Igal; Kivshar, Yuri S

2015-08-12

We experimentally demonstrate a functional silicon metadevice at telecom wavelengths that can efficiently control the wavefront of optical beams by imprinting a spatially varying transmittance phase independent of the polarization of the incident beam. Near-unity transmittance efficiency and close to 0-2π phase coverage are enabled by utilizing the localized electric and magnetic Mie-type resonances of low-loss silicon nanoparticles tailored to behave as electromagnetically dual-symmetric scatterers. We apply this concept to realize a metadevice that converts a Gaussian beam into a vortex beam. The required spatial distribution of transmittance phases is achieved by a variation of the lattice spacing as a single geometric control parameter.

Atmospheric, Magnetospheric and Plasmas in Space (AMPS) spacelab payload definition study. Volume 3: Interface control documents. Part 1: AMPS payload to shuttle ICD

NASA Technical Reports Server (NTRS)

1976-01-01

Physical, functional, and operational interfaces between the space shuttle orbiter and the AMPS payload are described for the ground handling and test phases, prelaunch, launch and ascent, operational, stowage, and reentry and landing activities.

JPL space station telerobotic engineering prototype development FY 91 status/achievements

NASA Technical Reports Server (NTRS)

Zimmerman, Wayne

1991-01-01

The topics covered are presented in view graph form and include: (1) streamlining intravehicular activity (IVA) teleoperation activities on the Space Station Freedom (SSF); (2) enhancing SSF utilization during the man-tended phase; (3) telerobotic ground remote operations (TGRO); and (4) advanced telerobotics system technology (shared control).

Appendange deployment mechanism for the Hubble Space Telescope program

NASA Technical Reports Server (NTRS)

Greenfield, H. T.

1985-01-01

The key requirements, a design overview, development testing (qualification levels), and two problems and their solutions resolved during the mechanism development testing phase are presented. The mechanism described herein has demonstrated its capability to deploy/restow two large Hubble Space Telescope deployable appendages in a varying but controlled manner.

Thermophotovoltaic space power system, phase 3

NASA Technical Reports Server (NTRS)

Horne, W. E.; Lancaster, C.

1987-01-01

Work performed on a research and development program to establish the feasibility of a solar thermophotovoltaic space power generation concept was summarized. The program was multiphased. The earlier work is summarized and the work on the current phase is detailed as it pertains to and extends the earlier work. Much of the experimental hardware and materials development was performed on the internal program. Experimental measurements and data evaluation were performed on the contracted effort. The objectives of the most recent phase were: to examine the thermal control design in order to optimize it for lightweight and low cost; to examine the concentrator optics in an attempt to relieve pointing accuracy requirements to + or - 2 degrees about the optical axis; and to use the results of the thermal and optical studies to synthesize a solar thermophotovoltaic (STPV) module design that is optimized for space application.

Integrated Digital Flight Control System for the Space Shuttle Orbiter

NASA Technical Reports Server (NTRS)

1973-01-01

The objectives of the integrated digital flight control system (DFCS) is to provide rotational and translational control of the space shuttle orbiter in all phases of flight: from launch ascent through orbit to entry and touchdown, and during powered horizontal flights. The program provides a versatile control system structure while maintaining uniform communications with other programs, sensors, and control effectors by using an executive routine/functional subroutine format. The program reads all external variables at a single point, copies them into its dedicated storage, and then calls the required subroutines in the proper sequence. As a result, the flight control program is largely independent of other programs in the computer complex and is equally insensitive to characteristics of the processor configuration. The integrated structure is described of the control system and the DFCS executive routine which embodies that structure. The input and output, including jet selection are included. Specific estimation and control algorithm are shown for the various mission phases: cruise (including horizontal powered flight), entry, on-orbit, and boost. Attitude maneuver routines that interface with the DFCS are included.

A study of aerodynamic heating distributions on a tip-fin controller installed on a Space Shuttle Orbiter model

NASA Technical Reports Server (NTRS)

Wittliff, C. E.

1982-01-01

The aerodynamic heating of a tip-fin controller mounted on a Space Shuttle Orbiter model was studied experimentally in the Calspan Advanced Technology Center 96 inch Hypersonic Shock Tunnel. A 0.0175 scale model was tested at Mach numbers from 10 to 17.5 at angles of attack typical of a shuttle entry. The study was conducted in two phases. In phase 1 testing a thermographic phosphor technique was used to qualitatively determine the areas of high heat-transfer rates. Based on the results of this phase, the model was instrumented with 40 thin-film resistance thermometers to obtain quantitative measurements of the aerodynamic heating. The results of the phase 2 testing indicate that the highest heating rates, which occur on the leading edge of the tip-fin controller, are very sensitive to angle of attack for alpha or = 30 deg. The shock wave from the leading edge of the orbiter wing impinges on the leading edge of the tip-fin controller resulting in peak values of h/h(Ref) in the range from 1.5 to 2.0. Away from the leading edge, the heat-transfer rates never exceed h/h(Ref) = 0.25 when the control surface, is not deflected. With the control surface deflected 20 deg, the heat-transfer rates had a maximum value of h/h(Ref) = 0.3. The heating rates are quite nonuniform over the outboard surface and are sensitive to angle of attack.

Automation of closed environments in space for human comfort and safety

NASA Technical Reports Server (NTRS)

1990-01-01

The Environmental Control and Life Support System (ECLSS) for the Space Station Freedom and future colonization of the Moon and Mars presents new challenges for present technologies. Current plans call for a crew of 8 to live in a safe, shirt-sleeve environment for 90 days without ground support. Because of these requirements, all life support systems must be self-sufficient and reliable. The ECLSS is composed of six subsystems. The temperature and humidity control (THC) subsystem maintains the cabin temperature and humidity at a comfortable level. The atmosphere control and supply (ACS) subsystem insures proper cabin pressure and partial pressures of oxygen and nitrogen. To protect the space station from fire damage, the fire detection and suppression (FDS) subsystem provides fire sensing alarms and extinguishers. The waste management (WM) subsystem compacts solid wastes for return to Earth, and collects urine for water recovery. Because it is impractical, if not impossible, to supply the station with enough fresh air and water for the duration of the space station's extended mission, these elements are recycled. The atmosphere revitalization (AR) subsystem removes CO2 and other dangerous contaminants from the air. The water recovery and management (WRM) subsystem collects and filters condensate from the cabin to replenish potable water supplies, and processes urine and other waste waters to replenish hygiene water supplies. These subsystems are not fully automated at this time. Furthermore, the control of these subsystems is not presently integrated; they are largely independent of one another. A fully integrated and automated ECLSS would increase astronauts' productivity and contribute to their safety and comfort. The Kansas State University Advanced Design Team is in the process of researching and designing controls for the automation of the ECLSS for Space Station Freedom and beyond. The approach chosen to solve this problem is to divide the design into three phases. The first phase is to research the ECLSS as a whole system and then concentrate efforts on the automation of a single subsystem. The AR subsystem was chosen for our focus. During the second phase, the system control process will then be applied to the AR subsystem.

Free-Piston Stirling Power Conversion Unit for Fission Power System, Phase II Final Report

NASA Technical Reports Server (NTRS)

Wood, J. Gary; Stanley, John

2016-01-01

In Phase II, the manufacture and testing of two 6-kW(sub e)Stirling engines was completed. The engines were delivered in an opposed 12-kW(sub e) arrangement with a common expansion space heater head. As described in the Phase I report, the engines were designed to be sealed both hermetically and with a bolted O-ring seal. The completed Phase II convertor is in the bolted configuration to allow future disassembly. By the end of Phase II, the convertor had passed all of the final testing requirements in preparation for delivery to the NASA Glenn Research Center. The electronic controller also was fabricated and tested during Phase II. The controller sets both piston amplitudes and maintains the phasing between them. It also sets the operating frequency of the machine. Details of the controller are described in the Phase I final report. Fabrication of the direct-current to direct-current (DC-DC) output stage, which would have stepped down the main controller output voltage from 700 to 120 V(sub DC), was omitted from this phase of the project for budgetary reasons. However, the main controller was successfully built, tested with the engines, and delivered. We experienced very few development issues with this high-power controller. The project extended significantly longer than originally planned because of yearly funding delays. The team also experienced several hardware difficulties along the development path. Most of these were related to the different thermal expansions of adjacent parts constructed of different materials. This issue was made worse by the large size of the machine. Thermal expansion problems also caused difficulties in the brazing of the opposed stainless steel sodium-potassium (NaK) heater head. Despite repeated attempts Sunpower was not able to successfully braze the opposed head under this project. Near the end of the project, Glenn fabricated an opposed Inconel NaK head, which was installed prior to delivery for testing at Glenn. Engine development prior to this was performed using both single- and dual-opposed (common expansion space) Inconel heads with clamp-on electric heaters.

International Space Station Environmental Control and Life Support System Status: 2002-2003

NASA Technical Reports Server (NTRS)

Wiliams, David E.; Lewis, John F.; Gentry, Gregory

2003-01-01

The International Space Station (ISS) Environmental Control and Life Support (ECLS) system includes regenerative and non-regenerative technologies that provide the basic life support functions to support the crew, while maintaining a safe and habitable shirtsleeve environment. This paper provides a summary of the U.S. ECLS system activities over the past year, covering the period of time between April 2002 and March 2003. The ISS continued permanent crew operations, with the start of Phase 3 of the ISS Assembly Sequence. Work continued on the Phase 3 pressurized elements with Node 3 just completing its final design review so that it can proceed towards manufacturing and the continued manufacturing of the regenerative ECLS equipment that will be integrated into Node 3.

Preliminary design of the Space Station internal thermal control system

NASA Technical Reports Server (NTRS)

Herrin, Mark T.; Patterson, David W.; Turner, Larry D.

1987-01-01

The baseline preliminary design configuration of the Internal Thermal Control system (ITCS) of the U.S. Space Station pressurized elements (i.e., the Habitation and U.S. Laboratory modules, pressurized logistics carrier, and resources nodes) is defined. The ITCS is composed of both active and passive components. The subsystems which comprise the ITCS are identified and their functional descriptions are provided. The significant trades and analyses, which were performed during Phase B (i.e., the preliminary design phase) that resulted in the design described herein, are discussed. The ITCS interfaces with the station's central Heat Rejection and Transport System (HRTS), other systems, and externally attached pressurized payloads are described. Requirements on the ITCS with regard to redundancy and experiment support are also addressed.

The manned space-laboratories control centre - MSCC. Operational functions and its implementation

NASA Astrophysics Data System (ADS)

Brogl, H.; Kehr, J.; Wlaka, M.

This paper describes the functions of the MSCC during the operations of the Columbus Attached Laboratory and the Free Flying Laboratory as part of the In-Orbit-Infrastructure Ground Segment. For the Attached Laboratory, MSCC payload operations coordination for European experiments within the Attached Laboratory and elsewhere on the Space Station Freedom will be explained. The Free Flying Laboratory will be operated and maintained exclusively from the MSCC during its 30 years lifetime. Several operational scenarios will demonstrate the role of the MSCC during routine - and servicing operations: of main importance are the servicing activities of the Attached Laboratory and the Free Flyer at the Space Station as well as servicing of the Free Flyer by the European Space Plane Hermes. The MSCC will have complex operational-, communications-and management interfaces with the IOI Ground Segment, the Space Station User community and with the international partners. Columbus User Support Centres will be established in many European member states, which have to be coordinated by the MSCC to ensure the proper reception of the scientific data and to provide them with quick access to their experiments in space. For operations planning and execution of experiments in the Attached Laboratory, a close cooperation with the Space Station control authorities in the USA will be established. The paper will show the development of the MSCC being initially used for the upcoming Spacelab Mission D-2 (MSCC Phase-1) and later upgraded to a Columbus dedicated control centre (MSCC Phase-2). For the initial construction phase the establishing of MSCC requirements, the philosophie used for the definition of the 'basic infrastructure' and key features of the installed facilities will be addressed. Resulting from Columbus and D-2 requirements, the sizing of the building with respect to controlrooms, conference rooms, office spare and simulation high-bay areas will be discussed. The defined 'basic infrastructure', consisting of standardized controlroom consoles, intercom system, video system, simulation system, timing system, public address system, office communications system and the associated networks will be presented with their main performance data. The D-2 data processing concept and associated interfaces is presented as well; although this portion of the MSCC facilities is unlikely to be used in later IOI operations activities the experience gathered during D-2 operations will be relevant for defining the Columbus (MSCC - Phase 2) configuration. A summary of the available budget and the allocation to the discussed MSCC Phase-1 facilities will be given. One chapter of the paper will present the current status and objectives of the Detailed Definition Phase (DDP) contract with industry. The last part of this presentation will address the planned implementation integration and test approach for the MSCC as a facility suitable for Columbus operations.

Toward large space systems. [Space Construction Base development from shuttles

NASA Technical Reports Server (NTRS)

Daros, C. J.; Freitag, R. F.; Kline, R. L.

1977-01-01

The design of the Space Transportation System, consisting of the Space Shuttle, Spacelab, and upper stages, provides experience for the development of more advanced space systems. The next stage will involve space stations in low earth orbit with limited self-sufficiency, characterized by closed ecological environments, space-generated power, and perhaps the first use of space materials. The third phase would include manned geosynchronous space-station activity and a return to lunar operations. Easier access to space will encourage the use of more complex, maintenance-requiring satellites than those currently used. More advanced space systems could perform a wide range of public services such as electronic mail, personal and police communication, disaster control, earthquake detection/prediction, water availability indication, vehicle speed control, and burglar alarm/intrusion detection. Certain products, including integrated-circuit chips and some enzymes, can be processed to a higher degree of purity in space and might eventually be manufactured there. Hardware including dishes, booms, and planar surfaces necessary for advanced space systems and their development are discussed.

Approximate solution of space and time fractional higher order phase field equation

NASA Astrophysics Data System (ADS)

Shamseldeen, S.

2018-03-01

This paper is concerned with a class of space and time fractional partial differential equation (STFDE) with Riesz derivative in space and Caputo in time. The proposed STFDE is considered as a generalization of a sixth-order partial phase field equation. We describe the application of the optimal homotopy analysis method (OHAM) to obtain an approximate solution for the suggested fractional initial value problem. An averaged-squared residual error function is defined and used to determine the optimal convergence control parameter. Two numerical examples are studied, considering periodic and non-periodic initial conditions, to justify the efficiency and the accuracy of the adopted iterative approach. The dependence of the solution on the order of the fractional derivative in space and time and model parameters is investigated.

Effective control of complex turbulent dynamical systems through statistical functionals.

PubMed

Majda, Andrew J; Qi, Di

2017-05-30

Turbulent dynamical systems characterized by both a high-dimensional phase space and a large number of instabilities are ubiquitous among complex systems in science and engineering, including climate, material, and neural science. Control of these complex systems is a grand challenge, for example, in mitigating the effects of climate change or safe design of technology with fully developed shear turbulence. Control of flows in the transition to turbulence, where there is a small dimension of instabilities about a basic mean state, is an important and successful discipline. In complex turbulent dynamical systems, it is impossible to track and control the large dimension of instabilities, which strongly interact and exchange energy, and new control strategies are needed. The goal of this paper is to propose an effective statistical control strategy for complex turbulent dynamical systems based on a recent statistical energy principle and statistical linear response theory. We illustrate the potential practical efficiency and verify this effective statistical control strategy on the 40D Lorenz 1996 model in forcing regimes with various types of fully turbulent dynamics with nearly one-half of the phase space unstable.

Japanese experiment module (JEM)

NASA Technical Reports Server (NTRS)

Kato, T.

1986-01-01

Japanese hardware elements studied during the definition phase of phase B are described. The hardware is called JEM (Japanese Experiment Module) and will be attached to the Space Station core. JEM consists of a pressurized module, an exposed facility, a scientific/equipment airlock, a local remote manipulator, and experimental logistic module. With all those hardware elements JEM will accommodate general scientific and technology development research (some of the elements are to utilize the advantage of the microgravity environment), and also accommodate control panels for the Space Station Mobile Remote Manipulator System and attached payloads.

Advanced Exploration Systems Water Architecture Study Interim Results

NASA Technical Reports Server (NTRS)

Sargusingh, Miriam J.

2013-01-01

The mission of the Advanced Exploration System (AES) Water Recovery Project (WRP) is to develop advanced water recovery systems that enable NASA human exploration missions beyond low Earth orbit (LEO). The primary objective of the AES WRP is to develop water recovery technologies critical to near-term missions beyond LEO. The secondary objective is to continue to advance mid-readiness-level technologies to support future NASA missions. An effort is being undertaken to establish the architecture for the AES Water Recovery System (WRS) that meets both near- and long-term objectives. The resultant architecture will be used to guide future technical planning, establish a baseline development roadmap for technology infusion, and establish baseline assumptions for integrated ground and on-orbit Environmental Control and Life Support Systems definition. This study is being performed in three phases. Phase I established the scope of the study through definition of the mission requirements and constraints, as well as identifying all possible WRS configurations that meet the mission requirements. Phase II focused on the near-term space exploration objectives by establishing an International Space Station-derived reference schematic for long-duration (>180 day) in-space habitation. Phase III will focus on the long-term space exploration objectives, trading the viable WRS configurations identified in Phase I to identify the ideal exploration WRS. The results of Phases I and II are discussed in this paper.

Conceptual design of a lunar base thermal control system

NASA Technical Reports Server (NTRS)

Simonsen, Lisa C.; Debarro, Marc J.; Farmer, Jeffery T.

1992-01-01

Space station and alternate thermal control technologies were evaluated for lunar base applications. The space station technologies consisted of single-phase, pumped water loops for sensible and latent heat removal from the cabin internal environment and two-phase ammonia loops for the transportation and rejection of these heat loads to the external environment. Alternate technologies were identified for those areas where space station technologies proved to be incompatible with the lunar environment. Areas were also identified where lunar resources could enhance the thermal control system. The internal acquisition subsystem essentially remained the same, while modifications were needed for the transport and rejection subsystems because of the extreme temperature variations on the lunar surface. The alternate technologies examined to accommodate the high daytime temperatures incorporated lunar surface insulating blankets, heat pump system, shading, and lunar soil. Other heat management techniques, such as louvers, were examined to prevent the radiators from freezing. The impact of the geographic location of the lunar base and the orientation of the radiators was also examined. A baseline design was generated that included weight, power, and volume estimates.

Statistics of the radiated field of a space-to-earth microwave power transfer system

NASA Technical Reports Server (NTRS)

Stevens, G. H.; Leininger, G.

1976-01-01

Statistics such as average power density pattern, variance of the power density pattern and variance of the beam pointing error are related to hardware parameters such as transmitter rms phase error and rms amplitude error. Also a limitation on spectral width of the phase reference for phase control was established. A 1 km diameter transmitter appears feasible provided the total rms insertion phase errors of the phase control modules does not exceed 10 deg, amplitude errors do not exceed 10% rms, and the phase reference spectral width does not exceed approximately 3 kHz. With these conditions the expected radiation pattern is virtually the same as the error free pattern, and the rms beam pointing error would be insignificant (approximately 10 meters).

Control strategy for a dual-arm maneuverable space robot

NASA Technical Reports Server (NTRS)

Wang, P. K. C.

1987-01-01

A simple strategy for the attitude control and arm coordination of a maneuverable space robot with dual arms is proposed. The basic task for the robot consists of the placement of marked rigid solid objects with specified pairs of gripping points and a specified direction of approach for gripping. The strategy consists of three phases each of which involves only elementary rotational and translational collision-free maneuvers of the robot body. Control laws for these elementary maneuvers are derived by using a body-referenced dynamic model of the dual-arm robot.

Operational training for the mission operations at the Brazilian National Institute for Space Research (INPE)

NASA Technical Reports Server (NTRS)

Rozenfeld, Pawel

1993-01-01

This paper describes the selection and training process of satellite controllers and data network operators performed at INPE's Satellite Tracking and Control Center in order to prepare them for the mission operations of the INPE's first (SCD1) satellite. An overview of the ground control system and SCD1 architecture and mission is given. Different training phases are described, taking into account that the applicants had no previous knowledge of space operations requiring, therefore, a training which started from the basics.

Revolutionary Concepts for Helicopter Noise Reduction: SILENT Program

NASA Technical Reports Server (NTRS)

Edwards, Bryan; Cox, Charles; Booth, Earl R., Jr. (Technical Monitor)

2002-01-01

As part of a NASA initiative to reduce helicopter main rotor noise, a Phase 1 study has been performed of candidate noise reduction concepts. Both conventional and novel design technologies have been analyzed that reduce the community impact of helicopter operations. In this study the noise reduction potential and design implications are assessed for conventional means of noise reduction, e.g., tip speed reduction, tip shapes and airfoil tailoring, and for two innovative design concepts: modulated blade spacing and x-force control. Main rotor designs that incorporate modulated blade spacing are shown to have reduced peak noise levels in most flight operations. X-force control alters the helicopter's force balance whereby the miss distance between main rotor blades and shed vortices can be controlled. This control provides a high potential to mitigate BVI noise radiation. Each concept is evaluated using best practice design and analysis methods, achieving the study's aim to significantly reduce noise with minimal performance degradation and no vibration increase. It is concluded that a SILENT main rotor design, incorporating the modulated blade spacing concept, offers significantly reduced noise levels and the potential of a breakthrough in how a helicopter's sound is perceived and judged. The SILENT rotor represents a definite advancement in the state-of-the-art and is selected as the design concept for demonstration in Phase 2. A Phase 2 Implementation Plan is developed for whirl cage and wind tunnel evaluations of a scaled model SILENT rotor.

RF MEMS and Their Applications in NASA's Space Communication Systems

NASA Technical Reports Server (NTRS)

Williams, W. Daniel; Ponchak, George E.; Simons, Rainee N.; Zaman, Afroz; Kory, Carol; Wintucky, Edwin; Wilson, Jeffrey D.; Scardelletti, Maximilian; Lee, Richard; Nguyen, Hung

2001-01-01

Radio frequency (RF) and microwave communication systems rely on frequency, amplitude, and phase control circuits to efficiently use the available spectrum. Phase control circuits are required for electronically scanning phase array antennas that enable radiation pattern shaping, scanning, and hopping. Two types of phase shifters, which are the phase control circuits, are most often used. The first is comprised of two circuits with different phase characteristics such as two transmission lines of different lengths or a high pass and low pass filter and a switch that directs the RF power through one of the two circuits. Alternatively, a variable capacitor, or varactor, is used to change the effective electrical path length of a transmission line, which changes the phase characteristics. Filter banks are required for the diplexer at the front end of wide band communication satellites. These filters greatly increase the size and mass of the RF/microwave systems, but smaller diplexers may be made with a low loss varactor or a group of capacitors, a switch and an inductor.

Detumbling control for kinematically redundant space manipulator post-grasping a rotational satellite

NASA Astrophysics Data System (ADS)

Wang, Mingming; Luo, Jianjun; Yuan, Jianping; Walter, Ulrich

2017-12-01

The objective of this paper is to establish a detumbling strategy and a coordination control scheme for a kinematically redundant space manipulator post-grasping a rotational satellite. First, the dynamics of the kinematically redundant space robot after grasping the target is presented, which lays the foundation for the coordination controller design. Subsequently, optimal detumbling and motion planning strategy for the post-capture phase is proposed based on the quartic Bézier curves and adaptive differential evolution (DE) algorithm subject to the specific constraints. Both detumbling time and control torques are taken into account for the generation of the optimal detumbling strategy. Furthermore, a coordination control scheme is presented to track the designed reference path while regulating the attitude of the chaser to a desired value, which successfully dumps the initial angular velocity of the rotational satellite and controls the base attitude synchronously. Simulation results are presented for detumbling a target with rotational motion using a 7 degree-of-freedom (DOF) redundant space manipulator, which demonstrates the effectiveness of the proposed method.

Wavefront Control Testbed (WCT) Experiment Results

NASA Technical Reports Server (NTRS)

Burns, Laura A.; Basinger, Scott A.; Campion, Scott D.; Faust, Jessica A.; Feinberg, Lee D.; Hayden, William L.; Lowman, Andrew E.; Ohara, Catherine M.; Petrone, Peter P., III

2004-01-01

The Wavefront Control Testbed (WCT) was created to develop and test wavefront sensing and control algorithms and software for the segmented James Webb Space Telescope (JWST). Last year, we changed the system configuration from three sparse aperture segments to a filled aperture with three pie shaped segments. With this upgrade we have performed experiments on fine phasing with line-of-sight and segment-to-segment jitter, dispersed fringe visibility and grism angle;. high dynamic range tilt sensing; coarse phasing with large aberrations, and sampled sub-aperture testing. This paper reviews the results of these experiments.

Analysis of Operational Factors Towards Achievement of Space Control...Transforming the Familiar

DTIC Science & Technology

1998-02-13

unsuitable for the day when enemy forces are capable of Space denial actions, requiring a change of philosophy in force architeture . For protection of...34 phase of the commander’s decision cycle is grotesquely out of proportion to the nature of warfare. The rapidly accelerating decision capability

Controlling propagation and coupling of waveguide modes using phase-gradient metasurfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Zhaoyi; Kim, Myoung -Hwan; Wang, Cheng

Here, research on two-dimensional designer optical structures, or metasurfaces, has mainly focused on controlling the wavefronts of light propagating in free space. Here, we show that gradient metasurface structures consisting of phased arrays of plasmonic or dielectric nanoantennas can be used to control guided waves via strong optical scattering at subwavelength intervals. Based on this design principle, we experimentally demonstrate waveguide mode converters, polarization rotators and waveguide devices supporting asymmetric optical power transmission. We also demonstrate all-dielectric on-chip polarization rotators based on phased arrays of Mie resonators with negligible insertion losses. Our gradient metasurfaces can enable small-footprint, broadband and low-lossmore » photonic integrated devices.« less

Optically controlled phased-array antenna technology for space communication systems

NASA Technical Reports Server (NTRS)

Kunath, Richard R.; Bhasin, Kul B.

1988-01-01

Using MMICs in phased-array applications above 20 GHz requires complex RF and control signal distribution systems. Conventional waveguide, coaxial cable, and microstrip methods are undesirable due to their high weight, high loss, limited mechanical flexibility and large volume. An attractive alternative to these transmission media, for RF and control signal distribution in MMIC phased-array antennas, is optical fiber. Presented are potential system architectures and their associated characteristics. The status of high frequency opto-electronic components needed to realize the potential system architectures is also discussed. It is concluded that an optical fiber network will reduce weight and complexity, and increase reliability and performance, but may require higher power.

Controlling propagation and coupling of waveguide modes using phase-gradient metasurfaces

DOE PAGES

Li, Zhaoyi; Kim, Myoung -Hwan; Wang, Cheng; ...

2017-04-17

Here, research on two-dimensional designer optical structures, or metasurfaces, has mainly focused on controlling the wavefronts of light propagating in free space. Here, we show that gradient metasurface structures consisting of phased arrays of plasmonic or dielectric nanoantennas can be used to control guided waves via strong optical scattering at subwavelength intervals. Based on this design principle, we experimentally demonstrate waveguide mode converters, polarization rotators and waveguide devices supporting asymmetric optical power transmission. We also demonstrate all-dielectric on-chip polarization rotators based on phased arrays of Mie resonators with negligible insertion losses. Our gradient metasurfaces can enable small-footprint, broadband and low-lossmore » photonic integrated devices.« less

Control of relative carrier-envelope phase slip in femtosecond Ti:sapphire and Cr:forsterite lasers.

PubMed

Kobayashi, Yohei; Torizuka, Kenji; Wei, Zhiyi

2003-05-01

We were able to control relative carrier-envelope phase slip among mode-locked Ti:sapphire and Cr:forsterite lasers by employing electronic feedback. The pulse timings of these lasers were passively synchronized with our crossing-beam technique. Since the optical-frequency ratio of Ti:sapphire and Cr:forsterite is approximately 3:2, we can observe the phase relation by superimposing the third harmonic of Cr:forsterite and the second harmonic of Ti:sapphire lasers in time and in space. The spectrum width of the locked beat note was less than 3 kHz, which corresponds to the controlled fluctuation of a cavity-length difference of less than 10 pm.

ACOSS FIVE (Active Control of Space Structures). Phase 1A

DTIC Science & Technology

1982-03-01

The control design MKUCTUKAL MOOC L PtRFOHMANCl MÜDtL DISTURBANCE MODEL I ’ II Q|S£) XM=) STATE SPACE MODEL KEDUCED MODELS (HAC... library ) whose detailed numerical procedures, structural reduction, eigen-computations, etc., are implemented dif- ferently than in NASTRAN. SPAR was...i-i. rCappesser ..ctn. ..ir. A. .^llliars i /ui N. t-t. i.yer orlva ..rlin^ton, ^\\ 22209 o j i c e 7 11 \\ttn. iULO Library

Flight Planning Branch Space Shuttle Lessons Learned

NASA Technical Reports Server (NTRS)

Price, Jennifer B.; Scott, Tracy A.; Hyde, Crystal M.

2011-01-01

Planning products and procedures that allow the mission flight control teams and the astronaut crews to plan, train and fly every Space Shuttle mission have been developed by the Flight Planning Branch at the NASA Johnson Space Center. As the Space Shuttle Program ends, lessons learned have been collected from each phase of the successful execution of these Shuttle missions. Specific examples of how roles and responsibilities of console positions that develop the crew and vehicle attitude timelines will be discussed, as well as techniques and methods used to solve complex spacecraft and instrument orientation problems. Additionally, the relationships and procedural hurdles experienced through international collaboration have molded operations. These facets will be explored and related to current and future operations with the International Space Station and future vehicles. Along with these important aspects, the evolution of technology and continual improvement of data transfer tools between the shuttle and ground team has also defined specific lessons used in the improving the control teams effectiveness. Methodologies to communicate and transmit messages, images, and files from Mission Control to the Orbiter evolved over several years. These lessons have been vital in shaping the effectiveness of safe and successful mission planning that have been applied to current mission planning work in addition to being incorporated into future space flight planning. The critical lessons from all aspects of previous plan, train, and fly phases of shuttle flight missions are not only documented in this paper, but are also discussed as how they pertain to changes in process and consideration for future space flight planning.

Cal Poly Space Project G-279

NASA Technical Reports Server (NTRS)

Farley, David R.

1987-01-01

The Cal Poly Space Project is an effort on the part of several highly motivated students to deploy a space canister which will examine the effects of microgravity on electroplating and immiscible metals. The experiments will be controlled and monitored by a specialized triple redundancy system developed to defer the possible electronic errors due to uncontrollable factors such as photons from the Sun. With the finalization of the payload design and the near completion of the data control system, the integration phase of the project is anticipated to be completed and the project ready for launching by early 1987. It is hoped that the experiments will lead to new insights in space research and also prove profitable to industry.

Quantum phase gate based on electromagnetically induced transparency in optical cavities

NASA Astrophysics Data System (ADS)

Borges, Halyne S.; Villas-Bôas, Celso J.

2016-11-01

We theoretically investigate the implementation of a quantum controlled-phase gate in a system constituted by a single atom inside an optical cavity, based on the electromagnetically induced transparency effect. First we show that a probe pulse can experience a π phase shift due to the presence or absence of a classical control field. Considering the interplay of the cavity-EIT effect and the quantum memory process, we demonstrated a controlled-phase gate between two single photons. To this end, first one needs to store a (control) photon in the ground atomic states. In the following, a second (target) photon must impinge on the atom-cavity system. Depending on the atomic state, this second photon will be either transmitted or reflected, acquiring different phase shifts. This protocol can then be easily extended to multiphoton systems, i.e., keeping the control photon stored, it may induce phase shifts in several single photons, thus enabling the generation of multipartite entangled states. We explore the relevant parameter space in the atom-cavity system that allows the implementation of quantum controlled-phase gates using the recent technologies. In particular, we have found a lower bound for the cooperativity of the atom-cavity system which enables the implementation of phase shift on single photons. The induced shift on the phase of a photonic qubit and the controlled-phase gate between single photons, combined with optical devices, enable one to perform universal quantum computation.

Effects of Weightlessness on Vestibular Development: Summary of Research on NIH.R1

NASA Technical Reports Server (NTRS)

Fritzsch, Bernd; Bruce, L. L.

1998-01-01

In our original application we proposed to investigate the effects of gravity on the formation of connections between the gravity receptors of the ear and the brain in rat pups raised in space beginning at an age before these connections are made until near the time of birth, when they are to some extent functional. We used the neuronal tracer, Dil, which could be applied to tissue obtained immediately after landing of the space shuttle, thus minimizing changes due to the earth's gravity. We hoped to determine whether the vestibular system develops in two phases, as do other sensory systems (such as the visual system). In these other systems the first phase of development is controlled genetically and the second phase is controlled by environmental stimulation. Our data collected strongly supports the idea that the vestibular system has these same two phases of development. The tissue obtained from the NIH.R1 experiment was of exceptionally high quality for our analysis. Therefore, we expanded our investigation into the ultrastructural effects of microgravity on vestibular development. For the sake of clarity we will subdivide our summary into two categories: (1) analysis of the branching pattern of axons between the vestibular nerve and the gravistatic receptors of the ear in flight and control animals, and (2) analysis of the branching pattern of axons between the vestibular nerve and the brain in flight and control animals.

WFL: Microwave Applications of Thin Ferroelectric Films

NASA Technical Reports Server (NTRS)

Romanofsky, Robert

2013-01-01

We have developed a family of tunable microwave circuits, operating from X- through Ka-band, based on laser ablated BaxSr1-xTiO films on lanthanum aluminate and magnesium oxide substrates. Circuits include voltage controlled oscillators, filters, phase shifters and antennas. A review of the basic theory of operation of these devices will be presented along with measured performance. Emphasis has been on low-loss phase shifters to enable a new phased array architecture. The critical role of phase shifter loss and transient response in reflectarray antennas will be discussed. The Ferroelectric Reflectarray Critical Components Space Experiment was launched on the penultimate Space Shuttle, STS-134, in May of 2011. It included a bank of ferroelectric phase shifters with two different stoichiometries as well as ancillary electronics. The experiment package and status will be reported. In addition, unusual results of a Van der Pauw measurement involving a ferroelectric film grown on buffered high resisitivity silicon will be discussed.

Design concepts and performance of NASA X-band transponder (DST) for deep space spacecraft applications

NASA Technical Reports Server (NTRS)

Mysoor, Narayan R.; Perret, Jonathan D.; Kermode, Arthur W.

1991-01-01

The design concepts and measured performance characteristics of an X band (7162 MHz/8415 MHz) breadboard deep space transponder (DST) for future spacecraft applications, with the first use scheduled for the Comet Rendezvous Asteroid Flyby (CRAF) and Cassini missions in 1995 and 1996, respectively. The DST consists of a double conversion, superheterodyne, automatic phase tracking receiver, and an X band (8415 MHz) exciter to drive redundant downlink power amplifiers. The receiver acquires and coherently phase tracks the modulated or unmodulated X band (7162 MHz) uplink carrier signal. The exciter phase modulates the X band (8415 MHz) downlink signal with composite telemetry and ranging signals. The receiver measured tracking threshold, automatic gain control static phase error, and phase jitter characteristics of the breadboard DST are in good agreement with the expected performance. The measured results show a receiver tracking threshold of -158 dBm and a dynamic signal range of 88 dB.

An X-band spacecraft transponder for deep space applications - Design concepts and breadboard performance

NASA Technical Reports Server (NTRS)

Mysoor, Narayan R.; Perret, Jonathan D.; Kermode, Arthur W.

1992-01-01

The design concepts and measured performance characteristics are summarized of an X band (7162 MHz/8415 MHz) breadboard deep space transponder (DSP) for future spacecraft applications, with the first use scheduled for the Comet Rendezvous Asteroid Flyby (CRAF) and Cassini missions in 1995 and 1996, respectively. The DST consists of a double conversion, superheterodyne, automatic phase tracking receiver, and an X band (8415 MHz) exciter to drive redundant downlink power amplifiers. The receiver acquires and coherently phase tracks the modulated or unmodulated X band (7162 MHz) uplink carrier signal. The exciter phase modulates the band (8415 MHz) downlink signal with composite telemetry and ranging signals. The receiver measured tracking threshold, automatic gain control, static phase error, and phase jitter characteristics of the breadboard DST are in good agreement with the expected performance. The measured results show a receiver tracking threshold of -158 dBm and a dynamic signal range of 88 dB.

Control of magnetohydrodynamic stability by phase space engineering of energetic ions in tokamak plasmas.

PubMed

Graves, J P; Chapman, I T; Coda, S; Lennholm, M; Albergante, M; Jucker, M

2012-01-10

Virtually collisionless magnetic mirror-trapped energetic ion populations often partially stabilize internally driven magnetohydrodynamic disturbances in the magnetosphere and in toroidal laboratory plasma devices such as the tokamak. This results in less frequent but dangerously enlarged plasma reorganization. Unique to the toroidal magnetic configuration are confined 'circulating' energetic particles that are not mirror trapped. Here we show that a newly discovered effect from hybrid kinetic-magnetohydrodynamic theory has been exploited in sophisticated phase space engineering techniques for controlling stability in the tokamak. These theoretical predictions have been confirmed, and the technique successfully applied in the Joint European Torus. Manipulation of auxiliary ion heating systems can create an asymmetry in the distribution of energetic circulating ions in the velocity orientated along magnetic field lines. We show the first experiments in which large sawtooth collapses have been controlled by this technique, and neoclassical tearing modes avoided, in high-performance reactor-relevant plasmas.

Phase space dynamics and control of the quantum particles associated to hypergraph states

NASA Astrophysics Data System (ADS)

Berec, Vesna

2015-05-01

As today's nanotechnology focus becomes primarily oriented toward production and manipulation of materials at the subatomic level, allowing the performance and complexity of interconnects where the device density accepts more than hundreds devices on a single chip, the manipulation of semiconductor nanostructures at the subatomic level sets its prime tasks on preserving and adequate transmission of information encoded in specified (quantum) states. The presented study employs the quantum communication protocol based on the hypergraph network model where the numerical solutions of equations of motion of quantum particles are associated to vertices (assembled with device chip), which follow specific controllable paths in the phase space. We address these findings towards ultimate quest for prediction and selective control of quantum particle trajectories. In addition, presented protocols could represent valuable tool for reducing background noise and uncertainty in low-dimensional and operationally meaningful, scalable complex systems.

Co-evolutionary data mining for fuzzy rules: automatic fitness function creation phase space, and experiments

NASA Astrophysics Data System (ADS)

Smith, James F., III; Blank, Joseph A.

2003-03-01

An approach is being explored that involves embedding a fuzzy logic based resource manager in an electronic game environment. Game agents can function under their own autonomous logic or human control. This approach automates the data mining problem. The game automatically creates a cleansed database reflecting the domain expert's knowledge, it calls a data mining function, a genetic algorithm, for data mining of the data base as required and allows easy evaluation of the information extracted. The co-evolutionary fitness functions, chromosomes and stopping criteria for ending the game are discussed. Genetic algorithm and genetic program based data mining procedures are discussed that automatically discover new fuzzy rules and strategies. The strategy tree concept and its relationship to co-evolutionary data mining are examined as well as the associated phase space representation of fuzzy concepts. The overlap of fuzzy concepts in phase space reduces the effective strategies available to adversaries. Co-evolutionary data mining alters the geometric properties of the overlap region known as the admissible region of phase space significantly enhancing the performance of the resource manager. Procedures for validation of the information data mined are discussed and significant experimental results provided.

Investigation and Feasibility Assessment of TOPAZ-2 Derivations for Space Power Applications

NASA Technical Reports Server (NTRS)

Parlos, Alexander G.; Peddicord, Kenneth L.

1998-01-01

The ability to provide continuous power at significant levels is of utmost importance for many space missions, from simple satellite operations to manned Mars missions. One of the main problems faced in delivering solar or chemical space power in the tens of kW range, is the increasingly massive nature of the power source and the costs associated with its launch, operation and maintenance. A national program had been initiated to study the feasibility of using certain advanced technologies in developing an efficient lightweight space power source. The starting point for these studies has been the Russian TOPAZ-2 space reactor system, with the ultimate goal to aid in the development of a TOPAZ-2 derivative which will be ready for flight by the year 2000. The main objective of this project has been to perform feasibility assessment and trade studies which would allow the development of an advanced space nuclear power system based on the in-core thermionic fuel element technology currently used in the Russian TOPAZ-2 reactor. Two of the important considerations in developing the concept are: (1) compliance of the current TOPAZ-2 and of any advanced designs with U.S. nuclear safety expectations, and (2) compliance of the design with the seven years lifetime requirement. The project was composed of two major phases. The initial phase of the project has concentrated on understanding the TOPAZ-2 thermionic reactor in sufficient detail to allow several follow-on tasks. The primary interest during this first phase has been given on identifying the potential of the TOPAZ-2 design for further improvements. The second phase of the project has focused on the feasibility of a TOPAZ-2 system capable of delivering 30-50 kWe. Towards the elimination of single-point failures in the load voltage regulation system an active voltage regulator has been designed to be used in conjunction with the available shunt load voltage regulator. The possible use of a dual-loop, model-based adaptive control system for load-following in the TOPAZ-2 has also been investigated. The objective of this fault-tolerant, autonomous control system is to deliver the demanded electric power at the desired voltage level, by appropriately manipulating the neutron power through the control drums. As a result, sufficient thermal power is produced to meet the required demand in the presence of dynamically changing system operating conditions and potential sensor failures. The designed controller is proposed for use in combination with the currently available shunt regulators, or as a back-up controller when other means of power system control, including some of the sensors, fail.

Cooperative control of two active spacecraft during proximity operations. M.S. Thesis - MIT

NASA Technical Reports Server (NTRS)

Polutchko, Robert J.

1989-01-01

A cooperative autopilot is developed for the control of the relative attitude, relative position and absolute attitude of two maneuvering spacecraft during on orbit proximity operations. The autopilot consists of an open-loop trajectory solver which computes a nine dimensional linearized nominal state trajectory at the beginning of each maneuver and a phase space regulator which maintains the two spacecraft on the nominal trajectory during coast phases of the maneuver. A linear programming algorithm is used to perform jet selection. Simulation tests using a system of two space shuttle vehicles are performed to verify the performance of the cooperative controller and comparisons are made to a traditional passive target/active pursuit vehicle approach to proximity operations. The cooperative autopilot is shown to be able to control the two vehicle system when both the would be pursuit vehicle and the target vehicle are not completely controllable in six degrees of freedom. The cooperative controller is also shown to use as much as 37 percent less fuel and 57 percent fewer jet firings than a single pursuit vehicle during a simple docking approach maneuver.

Thermal management of advanced fuel cell power systems

NASA Technical Reports Server (NTRS)

Vanderborgh, N. E.; Hedstrom, J.; Huff, J.

1990-01-01

It is shown that fuel cell devices are particularly attractive for the high-efficiency, high-reliability space hardware necessary to support upcoming space missions. These low-temperature hydrogen-oxygen systems necessarily operate with two-phase water. In either PEMFCs (proton exchange membrane fuel cells) or AFCs (alkaline fuel cells), engineering design must be critically focused on both stack temperature control and on the relative humidity control necessary to sustain appropriate conductivity within the ionic conductor. Water must also be removed promptly from the hardware. Present designs for AFC space hardware accomplish thermal management through two coupled cooling loops, both driven by a heat transfer fluid, and involve a recirculation fan to remove water and heat from the stack. There appears to be a certain advantage in using product water for these purposes within PEM hardware, because in that case a single fluid can serve both to control stack temperature, operating simultaneously as a heat transfer medium and through evaporation, and to provide the gas-phase moisture levels necessary to set the ionic conductor at appropriate performance levels. Moreover, the humidification cooling process automatically follows current loads. This design may remove the necessity for recirculation gas fans, thus demonstrating the long-term reliability essential for future space power hardware.

Electrical, Electronic, and Electromechanical (EEE) parts management and control requirements for NASA space flight programs

NASA Technical Reports Server (NTRS)

1989-01-01

This document establishes electrical, electronic, and electromechanical (EEE) parts management and control requirements for contractors providing and maintaining space flight and mission-essential or critical ground support equipment for NASA space flight programs. Although the text is worded 'the contractor shall,' the requirements are also to be used by NASA Headquarters and field installations for developing program/project parts management and control requirements for in-house and contracted efforts. This document places increased emphasis on parts programs to ensure that reliability and quality are considered through adequate consideration of the selection, control, and application of parts. It is the intent of this document to identify disciplines that can be implemented to obtain reliable parts which meet mission needs. The parts management and control requirements described in this document are to be selectively applied, based on equipment class and mission needs. Individual equipment needs should be evaluated to determine the extent to which each requirement should be implemented on a procurement. Utilization of this document does not preclude the usage of other documents. The entire process of developing and implementing requirements is referred to as 'tailoring' the program for a specific project. Some factors that should be considered in this tailoring process include program phase, equipment category and criticality, equipment complexity, and mission requirements. Parts management and control requirements advocated by this document directly support the concept of 'reliability by design' and are an integral part of system reliability and maintainability. Achieving the required availability and mission success objectives during operation depends on the attention given reliability and maintainability in the design phase. Consequently, it is intended that the requirements described in this document are consistent with those of NASA publications, 'Reliability Program Requirements for Aeronautical and Space System Contractors,' NHB 5300.4(1A-l); 'Maintainability Program Requirements for Space Systems,' NHB 5300.4(1E); and 'Quality Program Provisions for Aeronautical and Space System Contractors,' NHB 5300.4(1B).

An Improved Wavefront Control Algorithm for Large Space Telescopes

NASA Technical Reports Server (NTRS)

Sidick, Erkin; Basinger, Scott A.; Redding, David C.

2008-01-01

Wavefront sensing and control is required throughout the mission lifecycle of large space telescopes such as James Webb Space Telescope (JWST). When an optic of such a telescope is controlled with both surface-deforming and rigid-body actuators, the sensitivity-matrix obtained from the exit pupil wavefront vector divided by the corresponding actuator command value can sometimes become singular due to difference in actuator types and in actuator command values. In this paper, we propose a simple approach for preventing a sensitivity-matrix from singularity. We also introduce a new "minimum-wavefront and optimal control compensator". It uses an optimal control gain matrix obtained by feeding back the actuator commands along with the measured or estimated wavefront phase information to the estimator, thus eliminating the actuator modes that are not observable in the wavefront sensing process.

Space Operations Training Concepts Benchmark Study (Training in a Continuous Operations Environment)

NASA Technical Reports Server (NTRS)

Johnston, Alan E.; Gilchrist, Michael; Underwood, Debrah (Technical Monitor)

2002-01-01

The NASA/USAF Benchmark Space Operations Training Concepts Study will perform a comparative analysis of the space operations training programs utilized by the United States Air Force Space Command with those utilized by the National Aeronautics and Space Administration. The concentration of the study will be focused on Ground Controller/Flight Controller Training for the International Space Station Payload Program. The duration of the study is expected to be five months with report completion by 30 June 2002. The U.S. Air Force Space Command was chosen as the most likely candidate for this benchmark study because their experience in payload operations controller training and user interfaces compares favorably with the Payload Operations Integration Center's training and user interfaces. These similarities can be seen in the dynamics of missions/payloads, controller on-console requirements, and currency/proficiency challenges to name a few. It is expected that the report will look at the respective programs and investigate goals of each training program, unique training challenges posed by space operations ground controller environments, processes of setting up controller training programs, phases of controller training, methods of controller training, techniques to evaluate adequacy of controller knowledge and the training received, and approaches to training administration. The report will provide recommendations to the respective agencies based on the findings. Attached is a preliminary outline of the study. Following selection of participants and an approval to proceed, initial contact will be made with U.S. Air Force Space Command Directorate of Training to discuss steps to accomplish the study.

Practical Control Algorithms for Nonlinear Dynamical Systems Using Phase-Space Knowledge and Mixed Numeric and Geometric Computation.

DTIC Science & Technology

1997-10-01

Research results include: (1) Developed empirical performance criteria for characterizing stabilities and robustness of the maglev control... Maglev Experience’ at HS󈨥: Fifth International Hybrid Systems Workshop, Notre Dame, IN, Sept. 11-13,1997

German Contribution to the X-38 CRV Demonstrator in the Field of Guidance, Navigation and Control (GNC)

NASA Astrophysics Data System (ADS)

Soppa, Uwe; Görlach, Thomas; Roenneke, Axel Justus

2002-01-01

As a solution to meet a safety requirement to the future full scale space station infrastructure, the Crew Return/Rescue Vehicle (CRV) was supposed to supply the return capability for the complete ISS crew of 7 astronauts back to earth in case of an emergency. A prototype of such a vehicle named X-38 has been developed and built by NASA with European partnership (ESA, DLR). An series of aerial demonstrators (V13x) for tests of the subsonic TAEM phase and the parafoil descent and landing system has been flown by NASA from 1998 to 2001. A full scale unmanned space flight demonstrator (V201) has been built at JSC Houston and although the project has been stopped for budgetary reasons in 2002, it will hopefully still be flown in near future. The X-38 is a lifting body with hypersonic lift to drag ratio about 0.9. In comparison to the Space Shuttle Orbiter, this design provides less aerodynamic maneuvrability and a different actuator layout (divided body flap and winglet rudders instead as combined aileron and elevon in addition to thrust- ers for the early re-entry phase). Hence, the guidance and control concepts used onboard the shuttle orbiter had to be adapted and further developed for the application on the new vehicle. In the frame of the European share of the X-38 project and also of the German TETRA (TEchnol- ogy for future space TRAnsportation) project different GNC related contributions have been made: First, the primary flight control software for the autonomous guidance and control of the X-38 para- foil descent and landing phase has been developed, integrated and successfully flown on multiple vehicles and missions during the aerial drop test campaign conducted by NASA. Second, a real time X-38 vehicle simulator was provided to NASA which has also been used for the validation of a European re-entry guidance and control software (see below). According to the NASA verification and validation plan this simulator is supposed to be used as an independent vali- dation tool for the X-38 re-entry simulation and onboard software. Third, alternate guidance and control algorithms for the re-entry flight phase of X-38, using onboard flight path optimization for the guidance task and dynamic inversion control methods for attitude control have been developed. The resulting alternate guidance and control software shall be flown as a flight experiment onboard the V201 spaceflight test vehicle. Fourth, a fault tolerant computer similar to the one used onboard the ISS is planned to be integrated into the V201 spaceflight test vehicle as a host of the re-entry GNC software mentioned above. This paper will summarize the development and test phases of European guidance and control soft- ware and avionics elements for the different phases of the X-38 mission. Flight test results from the X38 aerial drop test campaigns will be presented and discussed. In addition, the flight experiment of the fault tolerant computer will be described.

Research on calibration error of carrier phase against antenna arraying

NASA Astrophysics Data System (ADS)

Sun, Ke; Hou, Xiaomin

2016-11-01

It is the technical difficulty of uplink antenna arraying that signals from various quarters can not be automatically aligned at the target in deep space. The size of the far-field power combining gain is directly determined by the accuracy of carrier phase calibration. It is necessary to analyze the entire arraying system in order to improve the accuracy of the phase calibration. This paper analyzes the factors affecting the calibration error of carrier phase of uplink antenna arraying system including the error of phase measurement and equipment, the error of the uplink channel phase shift, the position error of ground antenna, calibration receiver and target spacecraft, the error of the atmospheric turbulence disturbance. Discuss the spatial and temporal autocorrelation model of atmospheric disturbances. Each antenna of the uplink antenna arraying is no common reference signal for continuous calibration. So it must be a system of the periodic calibration. Calibration is refered to communication of one or more spacecrafts in a certain period. Because the deep space targets are not automatically aligned to multiplexing received signal. Therefore the aligned signal should be done in advance on the ground. Data is shown that the error can be controlled within the range of demand by the use of existing technology to meet the accuracy of carrier phase calibration. The total error can be controlled within a reasonable range.

Acoustic controlled rotation and orientation

NASA Technical Reports Server (NTRS)

Barmatz, Martin B. (Inventor); Allen, James L. (Inventor)

1989-01-01

Acoustic energy is applied to a pair of locations spaced about a chamber, to control rotation of an object levitated in the chamber. Two acoustic transducers applying energy of a single acoustic mode, one at each location, can (one or both) serve to levitate the object in three dimensions as well as control its rotation. Slow rotation is achieved by initially establishing a large phase difference and/or pressure ratio of the acoustic waves, which is sufficient to turn the object by more than 45 deg, which is immediately followed by reducing the phase difference and/or pressure ratio to maintain slow rotation. A small phase difference and/or pressure ratio enables control of the angular orientation of the object without rotating it. The sphericity of an object can be measured by its response to the acoustic energy.

The microprocessor-based synthesizer controller

NASA Technical Reports Server (NTRS)

Wick, M. R.

1980-01-01

Implementation and performance of the microprocessor-based controllers and Dana Digiphase Synthesizer (DCO) installed in the Deep Space Network exciter in the 64-meter and 34-meter subnets to support uplink tuning required for the Voyager-Saturn Encounter is discussed. Test data in tests conducted during the production of the controllers verified the design objective for phase control accuracy of 10 to the - 12 power cycles in eight hours during ramping. Tests conducted require a phase error between a theoretical calculated value and the actual phase of no greater than + or - 1 cycle. Tests included (1) a ramp over a period of eight hours using a ramp rate which covers the synthesizer tuning range (40-51 MHz) and (2) a ramp sequence using the maximum rate (+ or kHz/s) over the tuning range.

Summary Report on Phase I Results from the 3D Printing in Zero G Technology Demonstration Mission, Volume I

NASA Technical Reports Server (NTRS)

Prater, T. J.; Bean, Q. A.; Beshears, R. D.; Rolin, T. D.; Werkheiser, N. J.; Ordonez, E. A.; Ryan, R. M.; Ledbetter, F. E., III

2016-01-01

Human space exploration to date has been confined to low-Earth orbit and the Moon. The International Space Station (ISS) provides a unique opportunity for researchers to prove out the technologies that will enable humans to safely live and work in space for longer periods of time and venture beyond the Earth/Moon system. The ability to manufacture parts in-space rather than launch them from Earth represents a fundamental shift in the current risk and logistics paradigm for human spaceflight. In September 2014, NASA, in partnership with Made In Space, Inc., launched the 3D Printing in Zero-G technology demonstration mission to explore the potential of additive manufacturing for in-space applications and demonstrate the capability to manufacture parts and tools on orbit using fused deposition modeling. This Technical Publication summarizes the results of testing to date of the ground control and flight prints from the first phase of this ISS payload.

A system for conducting igneous petrology experiments under controlled redox conditions in reduced gravity

NASA Technical Reports Server (NTRS)

Williams, Richard J.

1987-01-01

The Space Shuttle and the planned Space Station will permit experimentation under conditions of reduced gravitational acceleration offering experimental petrologists the opportunity to study crystal growth, element distribution, and phase chemistry. In particular the confounding effects of macro and micro scale buoyancy-induced convection and crystal settling or flotation can be greatly reduced over those observed in experiments in the terrestrial laboratory. Also, for experiments in which detailed replication of the environment is important, the access to reduced gravity will permit a more complete simulation of processes that may have occurred on asteroids or in free space. A technique that was developed to control, measure, and manipulate oxygen fugacities with small quantities of gas which are recirculated over the sample. This system could be adaptable to reduced gravity space experiments requiring redox control.

Manned Mars mission accommodation: Sprint mission

NASA Technical Reports Server (NTRS)

Cirillo, William M.; Kaszubowski, Martin J.; Ayers, J. Kirk; Llewellyn, Charles P.; Weidman, Deene J.; Meredith, Barry D.

1988-01-01

The results of a study conducted at the NASA-LaRC to assess the impacts on the Phase 2 Space Station of Accommodating a Manned Mission to Mars are documented. In addition, several candidate transportation node configurations are presented to accommodate the assembly and verification of the Mars Mission vehicles. This study includes an identification of a life science research program that would need to be completed, on-orbit, prior to mission departure and an assessment of the necessary orbital technology development and demonstration program needed to accomplish the mission. Also included is an analysis of the configuration mass properties and a preliminary analysis of the Space Station control system sizing that would be required to control the station. Results of the study indicate the Phase 2 Space Station can support a manned mission to Mars with the addition of a supporting infrastructure that includes a propellant depot, assembly hangar, and a heavy lift launch vehicle to support the large launch requirements.

Energy storage and thermal control system design status. [for space station power supplies

NASA Technical Reports Server (NTRS)

Simons, Stephen N.; Willhoite, Bryan C.; Van Ommering, Gert

1989-01-01

The Space Station Freedom electric power system (EPS) will initially rely on photovoltaics for power generation and Ni/H2 batteries for electrical energy storage. The current design for the development status of two major subsystems in the PV Power Module is discussed. The energy storage subsystem comprised of high capacity Ni/H2 batteries and the single-phase thermal control system that rejects the excess heat generated by the batteries and other components associated with power generation andstorage is described.

Analysis, Implementation and Considerations for Liquid Crystals as a Reconfigurable Antennas Solution (LiCRAS) for Space

NASA Astrophysics Data System (ADS)

Doyle, Derek

The space industry has predominantly relied on high gain reflector dish antenna apertures for performing communications, but is constantly investing in phase array antenna concepts to provide increased signal flexibility at reduced system costs in terms of finances and system resources. The problem with traditional phased arrays remains the significantly greater program cost and complexity added to the satellite by integrating arrays of antenna elements with dedicated amplifier and phase shifters to perform adaptive beam forming. Liquid Crystal Reflectarrays (LiCRas) offer some of the electrical beam forming capability of a phased array system with the component and design complexity in lines with a traditional reflector antenna aperture but without the risks associated with mechanical steering systems. The final solution is believed to be a hybrid approach that performs in between the boundaries set by the two current disparate approaches. Practical reflectarrays have been developed since the 90's as a means to control reflection of incident radiation off a flat structure that is electrically curved based on radiating elements and their reflection characteristics with tailored element phase delay. In the last decade several methods have been proposed to enable tunable reflectarrays where the electrical shape of the reflector can be steered by controlling the resonating properties of the elements on the reflector using a DC bias. These approaches range from complex fast switching MEMS and ferroelectric devices, to more robust but slower chemical changes. The aim of this work is to investigate the feasibility of a molecular transition approach in the form of liquid crystals which change permittivity based on the electrical field they are subjected to. In this work, particular attention will be paid to the impact of space environment on liquid crystal reflectarray materials and reflector architectures. Of particular interest are the effects on performance induced by the temperature extremes of space and the electromagnetic particle environment. These two items tend to drive much of the research and development for various space technologies and based on these physical influences, assertions can be made toward the space worthiness of such a material approach and can layout future R&D; needs to make certain LC RF devices feasible for space use. Moreover, in this work the performance metrics of such a technology will be addressed along with methods of construction from a space perspective where specific design considerations must be made based on the extreme environment that a typical space asset must endure.

Realization of quantum gates with multiple control qubits or multiple target qubits in a cavity

NASA Astrophysics Data System (ADS)

Waseem, Muhammad; Irfan, Muhammad; Qamar, Shahid

2015-06-01

We propose a scheme to realize a three-qubit controlled phase gate and a multi-qubit controlled NOT gate of one qubit simultaneously controlling n-target qubits with a four-level quantum system in a cavity. The implementation time for multi-qubit controlled NOT gate is independent of the number of qubit. Three-qubit phase gate is generalized to n-qubit phase gate with multiple control qubits. The number of steps reduces linearly as compared to conventional gate decomposition method. Our scheme can be applied to various types of physical systems such as superconducting qubits coupled to a resonator and trapped atoms in a cavity. Our scheme does not require adjustment of level spacing during the gate implementation. We also show the implementation of Deutsch-Joza algorithm. Finally, we discuss the imperfections due to cavity decay and the possibility of physical implementation of our scheme.

Resonant Pump-dump Quantum Control of Solvated Dye Molecules with Phase Jumps

NASA Astrophysics Data System (ADS)

Konar, Arkaprabha; Lozovoy, Vadim; Dantus, Marcos

2014-03-01

Quantum coherent control of two photon and multiphoton excitation processes in atomic and condensed phase systems employing phase jumps has been well studied and understood. Here we demonstrate coherent quantum control of a two photon resonant pump-dump process in a complex solvated dye molecule. Phase jump in the frequency domain via a pulse shaper is employed to coherently enhance the stimulated emission by an order of magnitude when compared to transform limited pulses. Red shifted stimulated emission from successive low energy Stokes shifted excited states leading to narrowband emission are observed upon scanning the pi step across the excitation spectrum. A binary search space routine was also employed to investigate the effects of other types of phase jumps on stimulated emission and to determine the optimum phase that maximizes the emission. Understanding the underlying mechanism of this kind of enhancement will guide us in designing pulse shapes for enhancing stimulated emission, which can be further applied in the field of imaging.

Control of evaporation by geometry in capillary structures. From confined pillar arrays in a gap radial gradient to phyllotaxy-inspired geometry.

PubMed

Chen, Chen; Duru, Paul; Joseph, Pierre; Geoffroy, Sandrine; Prat, Marc

2017-11-08

Evaporation is a key phenomenon in the natural environment and in many technological systems involving capillary structures. Understanding the evaporation front dynamics enables the evaporation rate from microfluidic devices and porous media to be finely controlled. Of particular interest is the ability to control the position of the front through suitable design of the capillary structure. Here, we show how to design model capillary structures in microfluidic devices so as to control the drying kinetics. This is achieved by acting on the spatial organization of the constrictions that influence the invasion of the structure by the gas phase. Two types of control are demonstrated. The first is intended to control the sequence of primary invasions through the pore space, while the second aims to control the secondary liquid structures: films, bridges, etc., that can form in the region of pore space invaded by the gas phase. It is shown how the latter can be obtained from phyllotaxy-inspired geometry. Our study thus opens up a route toward the control of the evaporation kinetics by means of tailored capillary structures.

Space telescope optical telescope assembly/scientific instruments. Phase B: -Preliminary design and program definition study; Volume 2A: Planetary camera report

NASA Technical Reports Server (NTRS)

1976-01-01

Development of the F/48, F/96 Planetary Camera for the Large Space Telescope is discussed. Instrument characteristics, optical design, and CCD camera submodule thermal design are considered along with structural subsystem and thermal control subsystem. Weight, electrical subsystem, and support equipment requirements are also included.

Study of solid rocket motors for a space shuttle booster. Volume 3: Program acquisition planning

NASA Technical Reports Server (NTRS)

Vonderesch, A. H.

1972-01-01

Plans for conducting Phase C/D for a solid rocket motor booster vehicle are presented. Methods for conducting this program with details of scheduling, testing, and program management and control are included. The requirements of the space shuttle program to deliver a minimum cost/maximum reliability booster vehicle are examined.

Solar power satellite system definition study, phase 2. Volume 2: Reference system description

NASA Technical Reports Server (NTRS)

1979-01-01

System descriptions and cost estimates for the reference system of the solar power satellite program are presented. The reference system is divided into five principal elements: the solar power satellites; space construction and support; space and ground transportation; ground receiving stations; and operations control. The program scenario and non-recurring costs are briefly described.

High-resolution frequency measurement method with a wide-frequency range based on a quantized phase step law.

PubMed

Du, Baoqiang; Dong, Shaofeng; Wang, Yanfeng; Guo, Shuting; Cao, Lingzhi; Zhou, Wei; Zuo, Yandi; Liu, Dan

2013-11-01

A wide-frequency and high-resolution frequency measurement method based on the quantized phase step law is presented in this paper. Utilizing a variation law of the phase differences, the direct different frequency phase processing, and the phase group synchronization phenomenon, combining an A/D converter and the adaptive phase shifting principle, a counter gate is established in the phase coincidences at one-group intervals, which eliminates the ±1 counter error in the traditional frequency measurement method. More importantly, the direct phase comparison, the measurement, and the control between any periodic signals have been realized without frequency normalization in this method. Experimental results show that sub-picosecond resolution can be easily obtained in the frequency measurement, the frequency standard comparison, and the phase-locked control based on the phase quantization processing technique. The method may be widely used in navigation positioning, space techniques, communication, radar, astronomy, atomic frequency standards, and other high-tech fields.

Information management in an integrated space telerobot

NASA Technical Reports Server (NTRS)

Dipippo, S.; Pasquariello, G.; Labini, G. Sylos

1989-01-01

The in-orbit operations, like space structures inspection, servicing and repairing, is expected to be one of the most significant technological area for application and development of Robotics and Automation in Space Station environment. The Italian National Space Plan (PSN) has started up its strategic programme SPIDER (Space Inspection Device for Extravehicular Repairs), which is scheduled in three phases, with the final goal of performing docking and precision repairing in the Space Station environment. SPIDER system is an autonomous integrated space robot, using mature Artificial Intelligence tools and technics for its operational control. The preliminary results of a study on the information architecture of the spacecraft are described.

Advanced Health Management System for the Space Shuttle Main Engine

NASA Technical Reports Server (NTRS)

Davidson, Matt; Stephens, John

2004-01-01

Boeing-Canoga Park (BCP) and NASA-Marshall Space Flight Center (NASA-MSFC) are developing an Advanced Health Management System (AHMS) for use on the Space Shuttle Main Engine (SSME) that will improve Shuttle safety by reducing the probability of catastrophic engine failures during the powered ascent phase of a Shuttle mission. This is a phased approach that consists of an upgrade to the current Space Shuttle Main Engine Controller (SSMEC) to add turbomachinery synchronous vibration protection and addition of a separate Health Management Computer (HMC) that will utilize advanced algorithms to detect and mitigate predefined engine anomalies. The purpose of the Shuttle AHMS is twofold; one is to increase the probability of successfully placing the Orbiter into the intended orbit, and the other is to increase the probability of being able to safely execute an abort of a Space Transportation System (STS) launch. Both objectives are achieved by increasing the useful work envelope of a Space Shuttle Main Engine after it has developed anomalous performance during launch and the ascent phase of the mission. This increase in work envelope will be the result of two new anomaly mitigation options, in addition to existing engine shutdown, that were previously unavailable. The added anomaly mitigation options include engine throttle-down and performance correction (adjustment of engine oxidizer to fuel ratio), as well as enhanced sensor disqualification capability. The HMC is intended to provide the computing power necessary to diagnose selected anomalous engine behaviors and for making recommendations to the engine controller for anomaly mitigation. Independent auditors have assessed the reduction in Shuttle ascent risk to be on the order of 40% with the combined system and a three times improvement in mission success.

Values of the phase space factors for double beta decay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stoica, Sabin, E-mail: stoica@theory.nipne.ro; Mirea, Mihai; Horia Hulubei National Institute of Physics and Nuclear Engineering, 30 Reactorului street, P.O. Box MG6, Magurele

2015-10-28

We report an up-date list of the experimentally most interesting phase space factors for double beta decay (DBD). The electron/positron wave functions are obtained by solving the Dirac equations with a Coulomb potential derived from a realistic proton density distribution in nucleus and with inclusion of the finite nuclear size (FNS) and electron screening (ES) effects. We build up new numerical routines which allow us a good control of the accuracy of calculations. We found several notable differences as compared with previous results reported in literature and possible sources of these discrepancies are discussed.

Chaos, ergodic convergence, and fractal instability for a thermostated canonical harmonic oscillator

NASA Astrophysics Data System (ADS)

Hoover, Wm. G.; Hoover, Carol G.; Isbister, Dennis J.

2001-02-01

The authors thermostat a qp harmonic oscillator using the two additional control variables ζ and ξ to simulate Gibbs' canonical distribution. In contrast to the motion of purely Hamiltonian systems, the thermostated oscillator motion is completely ergodic, covering the full four-dimensional \\{q,p,ζ,ξ\\} phase space. The local Lyapunov spectrum (instantaneous growth rates of a comoving corotating phase-space hypersphere) exhibits singularities like those found earlier for Hamiltonian chaos, reinforcing the notion that chaos requires kinetic-as opposed to statistical-study, both at and away from equilibrium. The exponent singularities appear to have a fractal character.

MR thermometry characterization of a hyperthermia ultrasound array designed using the k-space computational method

PubMed Central

Al-Bataineh, Osama M; Collins, Christopher M; Park, Eun-Joo; Lee, Hotaik; Smith, Nadine Barrie

2006-01-01

Background Ultrasound induced hyperthermia is a useful adjuvant to radiation therapy in the treatment of prostate cancer. A uniform thermal dose (43°C for 30 minutes) is required within the targeted cancerous volume for effective therapy. This requires specific ultrasound phased array design and appropriate thermometry method. Inhomogeneous, acoustical, three-dimensional (3D) prostate models and economical computational methods provide necessary tools to predict the appropriate shape of hyperthermia phased arrays for better focusing. This research utilizes the k-space computational method and a 3D human prostate model to design an intracavitary ultrasound probe for hyperthermia treatment of prostate cancer. Evaluation of the probe includes ex vivo and in vivo controlled hyperthermia experiments using the noninvasive magnetic resonance imaging (MRI) thermometry. Methods A 3D acoustical prostate model was created using photographic data from the Visible Human Project®. The k-space computational method was used on this coarse grid and inhomogeneous tissue model to simulate the steady state pressure wavefield of the designed phased array using the linear acoustic wave equation. To ensure the uniformity and spread of the pressure in the length of the array, and the focusing capability in the width of the array, the equally-sized elements of the 4 × 20 elements phased array were 1 × 14 mm. A probe was constructed according to the design in simulation using lead zerconate titanate (PZT-8) ceramic and a Delrin® plastic housing. Noninvasive MRI thermometry and a switching feedback controller were used to accomplish ex vivo and in vivo hyperthermia evaluations of the probe. Results Both exposimetry and k-space simulation results demonstrated acceptable agreement within 9%. With a desired temperature plateau of 43.0°C, ex vivo and in vivo controlled hyperthermia experiments showed that the MRI temperature at the steady state was 42.9 ± 0.38°C and 43.1 ± 0.80°C, respectively, for 20 minutes of heating. Conclusion Unlike conventional computational methods, the k-space method provides a powerful tool to predict pressure wavefield in large scale, 3D, inhomogeneous and coarse grid tissue models. Noninvasive MRI thermometry supports the efficacy of this probe and the feedback controller in an in vivo hyperthermia treatment of canine prostate. PMID:17064421

MR thermometry characterization of a hyperthermia ultrasound array designed using the k-space computational method.

PubMed

Al-Bataineh, Osama M; Collins, Christopher M; Park, Eun-Joo; Lee, Hotaik; Smith, Nadine Barrie

2006-10-25

Ultrasound induced hyperthermia is a useful adjuvant to radiation therapy in the treatment of prostate cancer. A uniform thermal dose (43 degrees C for 30 minutes) is required within the targeted cancerous volume for effective therapy. This requires specific ultrasound phased array design and appropriate thermometry method. Inhomogeneous, acoustical, three-dimensional (3D) prostate models and economical computational methods provide necessary tools to predict the appropriate shape of hyperthermia phased arrays for better focusing. This research utilizes the k-space computational method and a 3D human prostate model to design an intracavitary ultrasound probe for hyperthermia treatment of prostate cancer. Evaluation of the probe includes ex vivo and in vivo controlled hyperthermia experiments using the noninvasive magnetic resonance imaging (MRI) thermometry. A 3D acoustical prostate model was created using photographic data from the Visible Human Project. The k-space computational method was used on this coarse grid and inhomogeneous tissue model to simulate the steady state pressure wavefield of the designed phased array using the linear acoustic wave equation. To ensure the uniformity and spread of the pressure in the length of the array, and the focusing capability in the width of the array, the equally-sized elements of the 4 x 20 elements phased array were 1 x 14 mm. A probe was constructed according to the design in simulation using lead zerconate titanate (PZT-8) ceramic and a Delrin plastic housing. Noninvasive MRI thermometry and a switching feedback controller were used to accomplish ex vivo and in vivo hyperthermia evaluations of the probe. Both exposimetry and k-space simulation results demonstrated acceptable agreement within 9%. With a desired temperature plateau of 43.0 degrees C, ex vivo and in vivo controlled hyperthermia experiments showed that the MRI temperature at the steady state was 42.9 +/- 0.38 degrees C and 43.1 +/- 0.80 degrees C, respectively, for 20 minutes of heating. Unlike conventional computational methods, the k-space method provides a powerful tool to predict pressure wavefield in large scale, 3D, inhomogeneous and coarse grid tissue models. Noninvasive MRI thermometry supports the efficacy of this probe and the feedback controller in an in vivo hyperthermia treatment of canine prostate.

Performance of a Ka-band transponder breadboard for deep-space applications

NASA Technical Reports Server (NTRS)

Mysoor, N. R.; Lane, J. P.; Kayalar, S.; Kermode, A. W.

1995-01-01

This article summarizes the design concepts applied in the development of and advanced Ka-band (34.4 GHz/32 GHz) transponder breadboard for the next generation of space communications systems applications. The selected architecture upgrades the X-band (7.2 GHz/8.4 GHz) deep-space transponder (DST) to provide Da-band up/Ka- and X-band down capability. The Ka-band transponder breadboard incorporates several state-of-the-art components, including sampling mixers, a Ka-band dielectric resonator oscillator, and microwave monolithic integrated circuits (MMICs). The MMICs that were tested in the breadboard include upconverters, downconverters, automatic gain control circuits, mixers, phase modulators, and amplifiers. The measured receiver dynamic range, tracking range, acquisition rate, static phase error, and phase jitter characteristics of the Ka-band breadboard interfaced to the advanced engineering model X-band DST are in good agreement with the expected performance. The results show a receiver tracking threshold of -149 dBm with a dynamic range of 80 dB and a downlink phase jitter of 7 deg rms. The analytical results of phase noise and Allan standard deviation are in good agreement with the experimental results.

Dynamic optical arbitrary waveform generation with amplitude controlled by interference of two FBG arrays.

PubMed

Zhang, Ailing; Li, Changxiu

2012-10-08

In this paper, a novel structure of dynamic optical arbitrary waveform generation (O-AWG) with amplitude controlled by interference of two fiber Bragg grating (FBG) arrays is proposed. The FBG array consists of several FBGs and fiber stretchers (FSs). The amplitude is controlled by FSs through interference of two FBG arrays. The phase is controlled by FSs simultaneously. As a result, optical pulse trains with various waveforms as well as pulse trains with nonuniform pulse intensity, pulse spacing and pulse width in each period are obtained via FSs adjustment to change the phase shift of signal in each array.

Flight Planning for the International Space Station - Levitation Observation of Dendrite Evolution in Steel Ternary Alloy Rapid Solidification (LODESTARS)

NASA Technical Reports Server (NTRS)

Flemings, Merton C.; Matson, Douglas M.; Hyers, Robert W.; Rogers, Jan R.

2003-01-01

During rapid solidification, a molten sample is cooled below its equilibrium solidification temperature to form a metastable liquid. Once nucleation is initiated, growth of the solid phase proceeds and can be seen as a sudden rise in temperature. The heat of fusion is rejected ahead of the growing dendrites into the undercooled liquid in a process known as recalescence. Fe-Cr-Ni alloys may form several equilibrium phases and the hypoeutectic alloys, with compositions near the commercially important 316 stainless steel alloy, are observed to solidify by way of a two-step process known as double recalescence. During double recalescence, the first temperature rise is associated with formation of the metastable ferritic solid phase with subsequent conversion to the stable austenitic phase during the second temperature rise. Selection of which phase grows into the undercooled melt during primary solidification may be accomplished by choice of the appropriate nucleation trigger material or by control of the processing parameters during rapid solidification. Due to the highly reactive nature of the molten sample material and in order to avoid contamination of the undercooled melt, a containerless electromagnetic levitation (EML) processing technique is used. In ground-based EML, the same forces that support the weight of the sample against gravity also drive convection in the liquid sample. However, in microgravity, the force required to position the sample is greatly reduced, so convection may be controlled over a wide range of internal flows. Space Shuttle experiments have shown that the double recalescence behavior of Fe-Cr-Ni alloys changes between ground and space EML experiments. This program is aimed at understanding how melt convection influences phase selection and the evolution of rapid solidification microstructures.

Polarization-independent silicon metadevices for efficient optical wavefront control

DOE PAGES

Chong, Katie E.; Staude, Isabelle; James, Anthony Randolph; ...

2015-07-20

In this study, we experimentally demonstrate a functional silicon metadevice at telecom wavelengths that can efficiently control the wavefront of optical beams by imprinting a spatially varying transmittance phase independent of the polarization of the incident beam. Near-unity transmittance efficiency and close to 0–2π phase coverage are enabled by utilizing the localized electric and magnetic Mie-type resonances of low-loss silicon nanoparticles tailored to behave as electromagnetically dual-symmetric scatterers. We apply this concept to realize a metadevice that converts a Gaussian beam into a vortex beam. The required spatial distribution of transmittance phases is achieved by a variation of the latticemore » spacing as a single geometric control parameter.« less

Polarization-independent silicon metadevices for efficient optical wavefront control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chong, Katie E.; Staude, Isabelle; James, Anthony Randolph

In this study, we experimentally demonstrate a functional silicon metadevice at telecom wavelengths that can efficiently control the wavefront of optical beams by imprinting a spatially varying transmittance phase independent of the polarization of the incident beam. Near-unity transmittance efficiency and close to 0–2π phase coverage are enabled by utilizing the localized electric and magnetic Mie-type resonances of low-loss silicon nanoparticles tailored to behave as electromagnetically dual-symmetric scatterers. We apply this concept to realize a metadevice that converts a Gaussian beam into a vortex beam. The required spatial distribution of transmittance phases is achieved by a variation of the latticemore » spacing as a single geometric control parameter.« less

Overcoming Dynamic Disturbances in Imaging Systems

NASA Technical Reports Server (NTRS)

Young, Eric W.; Dente, Gregory C.; Lyon, Richard G.; Chesters, Dennis; Gong, Qian

2000-01-01

We develop and discuss a methodology with the potential to yield a significant reduction in complexity, cost, and risk of space-borne optical systems in the presence of dynamic disturbances. More robust systems almost certainly will be a result as well. Many future space-based and ground-based optical systems will employ optical control systems to enhance imaging performance. The goal of the optical control subsystem is to determine the wavefront aberrations and remove them. Ideally reducing an aberrated image of the object under investigation to a sufficiently clear (usually diffraction-limited) image. Control will likely be distributed over several elements. These elements may include telescope primary segments, telescope secondary, telescope tertiary, deformable mirror(s), fine steering mirror(s), etc. The last two elements, in particular, may have to provide dynamic control. These control subsystems may become elaborate indeed. But robust system performance will require evaluation of the image quality over a substantial range and in a dynamic environment. Candidate systems for improvement in the Earth Sciences Enterprise could include next generation Landsat systems or atmospheric sensors for dynamic imaging of individual, severe storms. The technology developed here could have a substantial impact on the development of new systems in the Space Science Enterprise; such as the Next Generation Space Telescope(NGST) and its follow-on the Next NGST. Large Interferometric Systems of non-zero field, such as Planet Finder and Submillimeter Probe of the Evolution of Cosmic Structure, could benefit. These systems most likely will contain large, flexible optomechanical structures subject to dynamic disturbance. Furthermore, large systems for high resolution imaging of planets or the sun from space may also benefit. Tactical and Strategic Defense systems will need to image very small targets as well and could benefit from the technology developed here. We discuss a novel speckle imaging technique with the potential to separate dynamic aberrations from static aberrations. Post-processing of a set of image data, using an algorithm based on this technique, should work for all but the lowest light levels and highest frequency dynamic environments. This technique may serve to reduce the complexity of the control system and provide for robust, fault-tolerant, reduced risk operation. For a given object, a short exposure image is "frozen" on the focal plane in the presence of the environmental disturbance (turbulence, jitter, etc.). A key factor is that this imaging data exhibits frame-to-frame linear shift invariance. Therefore, although the Point Spread Function is varying from frame to frame, the source is fixed; and each short exposure contains object spectrum data out to the diffraction limit of the imaging system. This novel speckle imaging technique uses the Knox-Thompson method. The magnitude of the complex object spectrum is straightforward to determine by well-established approaches. The phase of the complex object spectrum is decomposed into two parts. One is a single-valued function determined by the divergence of the optical phase gradient. The other is a multi-valued function determined by the circulation of the optical phase gradient-"hidden phase." Finite difference equations are developed for the phase. The novelty of this approach is captured in the inclusion of this "hidden phase." This technique allows the diffraction-limited reconstruction of the object from the ensemble of short exposure frames while simultaneously estimating the phase as a function of time from a set of exposures.

Overcoming Dynamic Disturbances in Imaging Systems

NASA Technical Reports Server (NTRS)

Young, Eric W.; Dente, Gregory C.; Lyon, Richard G.; Chesters, Dennis; Gong, Qian

2000-01-01

We develop and discuss a methodology with the potential to yield a significant reduction in complexity, cost, and risk of space-borne optical systems in the presence of dynamic disturbances. More robust systems almost certainly will be a result as well. Many future space-based and ground-based optical systems will employ optical control systems to enhance imaging performance. The goal of the optical control subsystem is to determine the wavefront aberrations and remove them. Ideally reducing an aberrated image of the object under investigation to a sufficiently clear (usually diffraction-limited) image. Control will likely be distributed over several elements. These elements may include telescope primary segments, telescope secondary, telescope tertiary, deformable mirror(s), fine steering mirror(s), etc. The last two elements, in particular, may have to provide dynamic control. These control subsystems may become elaborate indeed. But robust system performance will require evaluation of the image quality over a substantial range and in a dynamic environment. Candidate systems for improvement in the Earth Sciences Enterprise could include next generation Landsat systems or atmospheric sensors for dynamic imaging of individual, severe storms. The technology developed here could have a substantial impact on the development of new systems in the Space Science Enterprise; such as the Next Generation Space Telescope(NGST) and its follow-on the Next NGST. Large Interferometric Systems of non-zero field, such as Planet Finder and Submillimeter Probe of the Evolution of Cosmic Structure, could benefit. These systems most likely will contain large, flexible optormechanical structures subject to dynamic disturbance. Furthermore, large systems for high resolution imaging of planets or the sun from space may also benefit. Tactical and Strategic Defense systems will need to image very small targets as well and could benefit from the technology developed here. We discuss a novel speckle imaging technique with the potential to separate dynamic aberrations from static aberrations. Post-processing of a set of image data, using an algorithm based on this technique, should work for all but the lowest light levels and highest frequency dynamic environments. This technique may serve to reduce the complexity of the control system and provide for robust, fault-tolerant, reduced risk operation. For a given object, a short exposure image is "frozen" on the focal plane in the presence of the environmental disturbance (turbulence, jitter, etc.). A key factor is that this imaging data exhibits frame-to-frame linear shift invariance. Therefore, although the Point Spread Function is varying from frame to frame, the source is fixed; and each short exposure contains object spectrum data out to the diffraction limit of the imaging system. This novel speckle imaging technique uses the Knox-Thompson method. The magnitude of the complex object spectrum is straightforward to determine by well-established approaches. The phase of the complex object spectrum is decomposed into two parts. One is a single-valued function determined by the divergence of the optical phase gradient. The other is a multi-valued function determined by, the circulation of the optical phase gradient-"hidden phase." Finite difference equations are developed for the phase. The novelty of this approach is captured in the inclusion of this "hidden phase." This technique allows the diffraction-limited reconstruction of the object from the ensemble of short exposure frames while simultaneously estimating the phase as a function of time from a set of exposures.

Effect of the Gouy phase on the coherent phase control of chemical reactions.

PubMed

Gordon, Robert J; Barge, Vishal J

2007-11-28

We show how the spatial phase of a focused laser beam may be used as a tool for controlling the branching ratio of a chemical reaction. Guoy discovered [Acad. Sci., Paris, C. R. 110, 1250 (1890)] that when an electromagnetic wave passes through a focus its phase increases by pi. In a coherent control scheme involving the absorption of n photons of frequency omega(m) and m photons of frequency omega(n), the overall phase shift produced by the Gouy phase is (n-m)pi. At any given point in space, this phase shift is identical for all reaction products. Nevertheless, if the yields for different reaction channels have different intensity dependencies, the Gouy phase produces a net phase lag between the products that varies with the axial coordinate of the laser focus. We obtain here analytical and numerical values of this phase as the laser focus is scanned across the diameter of the molecular beam, taking into account the Rayleigh range and astigmatism of the laser beam and saturation of the transition. We also show that the modulation depth of the interference pattern may be increased by optimizing the relative intensities of the two fields.

Design and Simulation of Control Technique for Permanent Magnet Synchronous Motor Using Space Vector Pulse Width Modulation

NASA Astrophysics Data System (ADS)

Khan, Mansoor; Yong, Wang; Mustafa, Ehtasham

2017-07-01

After the rapid advancement in the field of power electronics devices and drives for last few decades, there are different kinds of Pulse Width Modulation techniques which have been brought to the market. The applications ranging from industrial appliances to military equipment including the home appliances. The vey common application for the PWM is three phase voltage source inverter, which is used to convert DC to AC in the homes to supply the power to the house in case electricity failure, usually named as Un-interrupted Power Supply. In this paper Space Vector Pulse Width Modulation techniques is discussed and analysed under the control technique named as Field Oriented Control. The working and implementation of this technique has been studied by implementing on the three phase bridge inverter. The technique is used to control the Permanente Magnet Synchronous Motor. The drive system is successfully implemented in MATLAB/Simulink using the mathematical equation and algorithm to achieve the satisfactory results. PI type of controller is used to tuned ers of the motothe parametr i.e. torque and current.

Controlling Surface Plasmons Through Covariant Transformation of the Spin-Dependent Geometric Phase Between Curved Metamaterials

NASA Astrophysics Data System (ADS)

Zhong, Fan; Li, Jensen; Liu, Hui; Zhu, Shining

2018-06-01

General relativity uses curved space-time to describe accelerating frames. The movement of particles in different curved space-times can be regarded as equivalent physical processes based on the covariant transformation between different frames. In this Letter, we use one-dimensional curved metamaterials to mimic accelerating particles in curved space-times. The different curved shapes of structures are used to mimic different accelerating frames. The different geometric phases along the structure are used to mimic different movements in the frame. Using the covariant principle of general relativity, we can obtain equivalent nanostructures based on space-time transformations, such as the Lorentz transformation and conformal transformation. In this way, many covariant structures can be found that produce the same surface plasmon fields when excited by spin photons. A new kind of accelerating beam, the Rindler beam, is obtained based on the Rindler metric in gravity. Very large effective indices can be obtained in such systems based on geometric-phase gradient. This general covariant design method can be extended to many other optical media.

Gas-Liquid Two-Phase Flows Through Packed Bed Reactors in Microgravity

NASA Technical Reports Server (NTRS)

Motil, Brian J.; Balakotaiah, Vemuri

2001-01-01

The simultaneous flow of gas and liquid through a fixed bed of particles occurs in many unit operations of interest to the designers of space-based as well as terrestrial equipment. Examples include separation columns, gas-liquid reactors, humidification, drying, extraction, and leaching. These operations are critical to a wide variety of industries such as petroleum, pharmaceutical, mining, biological, and chemical. NASA recognizes that similar operations will need to be performed in space and on planetary bodies such as Mars if we are to achieve our goals of human exploration and the development of space. The goal of this research is to understand how to apply our current understanding of two-phase fluid flow through fixed-bed reactors to zero- or partial-gravity environments. Previous experiments by NASA have shown that reactors designed to work on Earth do not necessarily function in a similar manner in space. Two experiments, the Water Processor Assembly and the Volatile Removal Assembly have encountered difficulties in predicting and controlling the distribution of the phases (a crucial element in the operation of this type of reactor) as well as the overall pressure drop.

Space station advanced automation

NASA Technical Reports Server (NTRS)

Woods, Donald

1990-01-01

In the development of a safe, productive and maintainable space station, Automation and Robotics (A and R) has been identified as an enabling technology which will allow efficient operation at a reasonable cost. The Space Station Freedom's (SSF) systems are very complex, and interdependent. The usage of Advanced Automation (AA) will help restructure, and integrate system status so that station and ground personnel can operate more efficiently. To use AA technology for the augmentation of system management functions requires a development model which consists of well defined phases of: evaluation, development, integration, and maintenance. The evaluation phase will consider system management functions against traditional solutions, implementation techniques and requirements; the end result of this phase should be a well developed concept along with a feasibility analysis. In the development phase the AA system will be developed in accordance with a traditional Life Cycle Model (LCM) modified for Knowledge Based System (KBS) applications. A way by which both knowledge bases and reasoning techniques can be reused to control costs is explained. During the integration phase the KBS software must be integrated with conventional software, and verified and validated. The Verification and Validation (V and V) techniques applicable to these KBS are based on the ideas of consistency, minimal competency, and graph theory. The maintenance phase will be aided by having well designed and documented KBS software.

Autolysis of Escherichia coli and Bacillus subtilis cells in low gravity

NASA Technical Reports Server (NTRS)

Kacena, M. A.; Smith, E. E.; Todd, P.

1999-01-01

The role of gravity in the autolysis of Bacillus subtilis and Escherichia coli was studied by growing cells on Earth and in microgravity on Space Station Mir. Autolysis analysis was completed by examining the death phase or exponential decay of cells for approximately 4 months following the stationary phase. Consistent with published findings, the stationary-phase cell population was 170% and 90% higher in flight B. subtilis and E. coli cultures, respectively, than in ground cultures. Although both flight autolysis curves began at higher cell densities than control curves, the rate of autolysis in flight cultures was identical to that of their respective ground control rates.

Robust control of flexible space vehicles with minimum structural excitation: On-off pulse control of flexible space vehicles

NASA Technical Reports Server (NTRS)

Wie, Bong; Liu, Qiang

1992-01-01

Both feedback and feedforward control approaches for uncertain dynamical systems (in particular, with uncertainty in structural mode frequency) are investigated. The control objective is to achieve a fast settling time (high performance) and robustness (insensitivity) to plant uncertainty. Preshaping of an ideal, time optimal control input using a tapped-delay filter is shown to provide a fast settling time with robust performance. A robust, non-minimum-phase feedback controller is synthesized with particular emphasis on its proper implementation for a non-zero set-point control problem. It is shown that a properly designed, feedback controller performs well, as compared with a time optimal open loop controller with special preshaping for performance robustness. Also included are two separate papers by the same authors on this subject.

Glassy phase in quenched disordered crystalline membranes

NASA Astrophysics Data System (ADS)

Coquand, O.; Essafi, K.; Kownacki, J.-P.; Mouhanna, D.

2018-03-01

We investigate the flat phase of D -dimensional crystalline membranes embedded in a d -dimensional space and submitted to both metric and curvature quenched disorders using a nonperturbative renormalization group approach. We identify a second-order phase transition controlled by a finite-temperature, finite-disorder fixed point unreachable within the leading order of ɛ =4 -D and 1 /d expansions. This critical point divides the flow diagram into two basins of attraction: that associated with the finite-temperature fixed point controlling the long-distance behavior of disorder-free membranes and that associated with the zero-temperature, finite-disorder fixed point. Our work thus strongly suggests the existence of a whole low-temperature glassy phase for quenched disordered crystalline membranes and, possibly, for graphene and graphene-like compounds.

Design and Analysis of an Axisymmetric Phased Array Fed Gregorian Reflector System for Limited Scanning

DTIC Science & Technology

2016-01-22

applications. For space applications, attitude control systems can provide good angular control of the antenna aperture with small residual angular...Bilyeu, and G.R. Veal, Development of Flight Hardware for a Large Inflatable- Deployable Antenna Experiment , Acta Astronautica, Vol. 38, Nos. 4-8

Renal hemodynamics in space.

PubMed

Kramer, H J; Heer, M; Cirillo, M; De Santo, N G

2001-09-01

Renal excretory function and hemodynamics are determined by the effective circulating plasma volume as well as by the interplay of systemic and local vasoconstrictors and vasodilators. Microgravity results in a headward shift of body fluid. Because the control conditions of astronauts were poorly defined in many studies, controversial results have been obtained regarding diuresis and natriuresis as well as renal hemodynamic changes in response to increased central blood volume, especially during the initial phase of space flight. Renal excretory function and renal hemodynamics in microgravity are affected in a complex fashion, because during the initial phase of space flight, variable mechanisms become operative to modulate the effects of increased central blood volume. They include interactions between vasodilators (dopamine, atrial natriuretic peptide, and prostaglandins) and vasoconstrictors (sympathetic nervous system and the renin-angiotensin system). The available data suggest a moderate rise in glomerular filtration rate during the first 2 days after launch without a significant increase in effective renal plasma flow. In contrast, too few data regarding the effects of space flight on renal function during the first 12 hours after launch are available and are, in addition, partly contradictory. Thus, detailed and well-controlled studies are required to shed more light on the role of the various factors besides microgravity that determine systemic and renal hemodynamics and renal excretory function during the different stages of space flight.

Technology transfer of military space microprocessor developments

NASA Astrophysics Data System (ADS)

Gorden, C.; King, D.; Byington, L.; Lanza, D.

1999-01-01

Over the past 13 years the Air Force Research Laboratory (AFRL) has led the development of microprocessors and computers for USAF space and strategic missile applications. As a result of these Air Force development programs, advanced computer technology is available for use by civil and commercial space customers as well. The Generic VHSIC Spaceborne Computer (GVSC) program began in 1985 at AFRL to fulfill a deficiency in the availability of space-qualified data and control processors. GVSC developed a radiation hardened multi-chip version of the 16-bit, Mil-Std 1750A microprocessor. The follow-on to GVSC, the Advanced Spaceborne Computer Module (ASCM) program, was initiated by AFRL to establish two industrial sources for complete, radiation-hardened 16-bit and 32-bit computers and microelectronic components. Development of the Control Processor Module (CPM), the first of two ASCM contract phases, concluded in 1994 with the availability of two sources for space-qualified, 16-bit Mil-Std-1750A computers, cards, multi-chip modules, and integrated circuits. The second phase of the program, the Advanced Technology Insertion Module (ATIM), was completed in December 1997. ATIM developed two single board computers based on 32-bit reduced instruction set computer (RISC) processors. GVSC, CPM, and ATIM technologies are flying or baselined into the majority of today's DoD, NASA, and commercial satellite systems.

The Final Count Down: A Review of Three Decades of Flight Controller Training Methods for Space Shuttle Mission Operations

NASA Technical Reports Server (NTRS)

Dittermore, Gary; Bertels, Christie

2011-01-01

Operations of human spaceflight systems is extremely complex; therefore, the training and certification of operations personnel is a critical piece of ensuring mission success. Mission Control Center (MCC-H), at the Lyndon B. Johnson Space Center in Houston, Texas, manages mission operations for the Space Shuttle Program, including the training and certification of the astronauts and flight control teams. An overview of a flight control team s makeup and responsibilities during a flight, and details on how those teams are trained and certified, reveals that while the training methodology for developing flight controllers has evolved significantly over the last thirty years the core goals and competencies have remained the same. In addition, the facilities and tools used in the control center have evolved. Changes in methodology and tools have been driven by many factors, including lessons learned, technology, shuttle accidents, shifts in risk posture, and generational differences. Flight controllers share their experiences in training and operating the space shuttle. The primary training method throughout the program has been mission simulations of the orbit, ascent, and entry phases, to truly train like you fly. A review of lessons learned from flight controller training suggests how they could be applied to future human spaceflight endeavors, including missions to the moon or to Mars. The lessons learned from operating the space shuttle for over thirty years will help the space industry build the next human transport space vehicle.

The Right Stuff: A Look Back at Three Decades of Flight Controller Training for Space Shuttle Mission Operations

NASA Technical Reports Server (NTRS)

Dittemore, Gary D.

2011-01-01

Operations of human spaceflight systems is extremely complex, therefore the training and certification of operations personnel is a critical piece of ensuring mission success. Mission Control Center (MCC-H), at the Lyndon B. Johnson Space Center, in Houston, Texas manages mission operations for the Space Shuttle Program, including the training and certification of the astronauts and flight control teams. This paper will give an overview of a flight control team s makeup and responsibilities during a flight, and details on how those teams are trained and certified. The training methodology for developing flight controllers has evolved significantly over the last thirty years, while the core goals and competencies have remained the same. In addition, the facilities and tools used in the control center have evolved. These changes have been driven by many factors including lessons learned, technology, shuttle accidents, shifts in risk posture, and generational differences. Flight controllers will share their experiences in training and operating the Space Shuttle throughout the Program s history. A primary method used for training Space Shuttle flight control teams is by running mission simulations of the orbit, ascent, and entry phases, to truly "train like you fly." The reader will learn what it is like to perform a simulation as a shuttle flight controller. Finally, the paper will reflect on the lessons learned in training for the shuttle program, and how those could be applied to future human spaceflight endeavors. These endeavors could range from going to the moon or to Mars. The lessons learned from operating the space shuttle for over thirty years will help the space industry build the next human transport space vehicle and inspire the next generation of space explorers.

Quantifying the entropic cost of cellular growth control

NASA Astrophysics Data System (ADS)

De Martino, Daniele; Capuani, Fabrizio; De Martino, Andrea

2017-07-01

Viewing the ways a living cell can organize its metabolism as the phase space of a physical system, regulation can be seen as the ability to reduce the entropy of that space by selecting specific cellular configurations that are, in some sense, optimal. Here we quantify the amount of regulation required to control a cell's growth rate by a maximum-entropy approach to the space of underlying metabolic phenotypes, where a configuration corresponds to a metabolic flux pattern as described by genome-scale models. We link the mean growth rate achieved by a population of cells to the minimal amount of metabolic regulation needed to achieve it through a phase diagram that highlights how growth suppression can be as costly (in regulatory terms) as growth enhancement. Moreover, we provide an interpretation of the inverse temperature β controlling maximum-entropy distributions based on the underlying growth dynamics. Specifically, we show that the asymptotic value of β for a cell population can be expected to depend on (i) the carrying capacity of the environment, (ii) the initial size of the colony, and (iii) the probability distribution from which the inoculum was sampled. Results obtained for E. coli and human cells are found to be remarkably consistent with empirical evidence.

Current harmonics elimination control method for six-phase PM synchronous motor drives.

PubMed

Yuan, Lei; Chen, Ming-liang; Shen, Jian-qing; Xiao, Fei

2015-11-01

To reduce the undesired 5th and 7th stator harmonic current in the six-phase permanent magnet synchronous motor (PMSM), an improved vector control algorithm was proposed based on vector space decomposition (VSD) transformation method, which can control the fundamental and harmonic subspace separately. To improve the traditional VSD technology, a novel synchronous rotating coordinate transformation matrix was presented in this paper, and only using the traditional PI controller in d-q subspace can meet the non-static difference adjustment, the controller parameter design method is given by employing internal model principle. Moreover, the current PI controller parallel with resonant controller is employed in x-y subspace to realize the specific 5th and 7th harmonic component compensation. In addition, a new six-phase SVPWM algorithm based on VSD transformation theory is also proposed. Simulation and experimental results verify the effectiveness of current decoupling vector controller. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Fluid management in space construction

NASA Technical Reports Server (NTRS)

Snyder, Howard

1989-01-01

The low-g fluids management group with the Center for Space Construction is engaged in active research on the following topics: gauging; venting; controlling contamination; sloshing; transfer; acquisition; and two-phase flow. Our basic understanding of each of these topics at present is inadequate to design space structures optimally. A brief report is presented on each topic showing the present status, recent accomplishings by our group and our plans for future research. Reports are presented in graphic and outline form.

Two dimensional thermo-optic beam steering using a silicon photonic optical phased array

NASA Astrophysics Data System (ADS)

Mahon, Rita; Preussner, Marcel W.; Rabinovich, William S.; Goetz, Peter G.; Kozak, Dmitry A.; Ferraro, Mike S.; Murphy, James L.

2016-03-01

Components for free space optical communication terminals such as lasers, amplifiers, and receivers have all seen substantial reduction in both size and power consumption over the past several decades. However, pointing systems, such as fast steering mirrors and gimbals, have remained large, slow and power-hungry. Optical phased arrays provide a possible solution for non-mechanical beam steering devices that can be compact and lower in power. Silicon photonics is a promising technology for phased arrays because it has the potential to scale to many elements and may be compatible with CMOS technology thereby enabling batch fabrication. For most free space optical communication applications, two-dimensional beam steering is needed. To date, silicon photonic phased arrays have achieved two-dimensional steering by combining thermo-optic steering, in-plane, with wavelength tuning by means of an output grating to give angular tuning, out-of-plane. While this architecture might work for certain static communication links, it would be difficult to implement for moving platforms. Other approaches have required N2 controls for an NxN element phased array, which leads to complexity. Hence, in this work we demonstrate steering using the thermo-optic effect for both dimensions with a simplified steering mechanism requiring only two control signals, one for each steering dimension.

Control of a free-flying robot manipulator system

NASA Technical Reports Server (NTRS)

Alexander, H.

1986-01-01

The development of and test control strategies for self-contained, autonomous free flying space robots are discussed. Such a robot would perform operations in space similar to those currently handled by astronauts during extravehicular activity (EVA). Use of robots should reduce the expense and danger attending EVA both by providing assistance to astronauts and in many cases by eliminating altogether the need for human EVA, thus greatly enhancing the scope and flexibility of space assembly and repair activities. The focus of the work is to develop and carry out a program of research with a series of physical Satellite Robot Simulator Vehicles (SRSV's), two-dimensionally freely mobile laboratory models of autonomous free-flying space robots such as might perform extravehicular functions associated with operation of a space station or repair of orbiting satellites. It is planned, in a later phase, to extend the research to three dimensions by carrying out experiments in the Space Shuttle cargo bay.

Variable Structure Control of a Hand-Launched Glider

NASA Technical Reports Server (NTRS)

Anderson, Mark R.; Waszak, Martin R.

2005-01-01

Variable structure control system design methods are applied to the problem of aircraft spin recovery. A variable structure control law typically has two phases of operation. The reaching mode phase uses a nonlinear relay control strategy to drive the system trajectory to a pre-defined switching surface within the motion state space. The sliding mode phase involves motion along the surface as the system moves toward an equilibrium or critical point. Analysis results presented in this paper reveal that the conventional method for spin recovery can be interpreted as a variable structure controller with a switching surface defined at zero yaw rate. Application of Lyapunov stability methods show that deflecting the ailerons in the direction of the spin helps to insure that this switching surface is stable. Flight test results, obtained using an instrumented hand-launched glider, are used to verify stability of the reaching mode dynamics.

Delta space plot analysis of cardiovascular coupling in vasovagal syncope during orthostatic challenge.

PubMed

Reulecke, S; Charleston-Villalobos, S; Voss, A; Gonzalez-Camarena, R; Gaitan-Gonzalez, M; Gonzalez-Hermosillo, J; Hernandez-Pacheco, G; Aljama-Corrales, T

2016-08-01

In this work, a graphical method to study cardiovascular coupling, called delta space plot analysis (DSPA), was introduced. The graphical representation is susceptible to be parameterized in shape and orientation. The usefulness of this technique was studied on cardiovascular data from patients with vasovagal syncope (VVS) and from controls. The study included 15 female patients diagnosed with VVS and 11 age-matched healthy female subjects. All subjects were enrolled in a head-up tilt (HUT) test, breathing normally, including 5 minutes of supine position (baseline) and 18 minutes of 70° orthostatic phase. The DSPA parameters were obtained at different times during the HUT test, i.e., at baseline, early (first 5 min) and late (10-15 min) orthostatic phases. In baseline there were no considerable differences between female controls and female patients. During the late orthostatic phase, parameters from DSPA showed highly significantly (p=0.000003) reduced cardiovascular coupling in patients. Findings indicated a loss of control on cardiovascular coupling in female patients susceptible to vasovagal syncope during orthostatic challenge. In addition, this study provided promising results for a new graphical method to investigate cardiovascular coupling.

Scintillation Effects on Space Shuttle GPS Data

NASA Technical Reports Server (NTRS)

Goodman, John L.; Kramer, Leonard

2001-01-01

Irregularities in ionospheric electron density result in variation in amplitude and phase of Global Positioning System (GPS) signals, or scintillation. GPS receivers tracking scintillated signals may lose carrier phase or frequency lock in the case of phase sc intillation. Amplitude scintillation can cause "enhancement" or "fading" of GPS signals and result in loss of lock. Scintillation can occur over the equatorial and polar regions and is a function of location, time of day, season, and solar and geomagnetic activity. Mid latitude regions are affected only very rarely, resulting from highly disturbed auroral events. In the spring of 1998, due to increasing concern about scintillation of GPS signals during the upcoming solar maximum, the Space Shuttle Program began to assess the impact of scintillation on Collins Miniaturized Airborne GPS Receiver (MAGR) units that are to replace Tactical Air Control and Navigation (TACAN) units on the Space Shuttle orbiters. The Shuttle Program must determine if scintillation effects pose a threat to safety of flight and mission success or require procedural and flight rule changes. Flight controllers in Mission Control must understand scintillation effects on GPS to properly diagnose "off nominal" GPS receiver performance. GPS data from recent Space Shuttle missions indicate that the signals tracked by the Shuttle MAGR manifest scintillation. Scintillation is observed as anomalous noise in velocity measurements lasting for up to 20 minutes on Shuttle orbit passes and are not accounted for in the error budget of the MAGR accuracy parameters. These events are typically coincident with latitude and local time occurrence of previously identified equatorial spread F within about 20 degrees of the magnetic equator. The geographic and seasonal history of these events from ground-based observations and a simple theoretical model, which have potential for predicting events for operational purposes, are reviewed.

The Space Station Freedom Flight Telerobotic Servicer - The design and evolution of a dexterous space robot

NASA Technical Reports Server (NTRS)

Mccain, Harry G.; Andary, James F.; Hewitt, Dennis R.; Haley, Dennis C.

1990-01-01

The Flight Telerobotic Servicer (FTS) will provide a telerobotic capability to the Space Station in the early assembly phases of the program and will be used for assembly, maintenance, and inspection throughout the lifetime of the Station. Here, the FTS design approach to the development of autonomous capabilities is discussed. The FTS telerobotic workstations for the Shuttle and Space Station, and facility for on-orbit storage are examined. The rationale of the FTS with regard to ease of operation, operational versatility, maintainability, safety, and control is discussed.

International Space Station Program Phase 3 Integrated Atmosphere Revitalization Subsystem Test

NASA Technical Reports Server (NTRS)

Perry, J. L.; Franks, G. D.; Knox, J. C.

1997-01-01

Testing of the International Space Station (ISS) U.S. Segment baseline configuration of the Atmosphere Revitalization Subsystem (ARS) by NASA's Marshall Space Flight Center (MSFC) was conducted as part of the Environmental Control and Life Support System (ECLSS) design and development program. This testing was designed to answer specific questions regarding the control and performance of the baseline ARS subassemblies in the ISS U.S. Segment configuration. These questions resulted from the continued maturation of the ISS ECLSS configuration and design requirement changes since 1992. The test used pressurized oxygen injection, a mass spectrometric major constituent analyzer, a Four-Bed Molecular Sieve Carbon Dioxide Removal Assembly, and a Trace Contaminant Control Subassembly to maintain the atmospheric composition in a sealed chamber at ISS specifications for 30 days. Human metabolic processes for a crew of four were simulated according to projected ISS mission time lines. The performance of a static feed water electrolysis Oxygen Generator Assembly was investigated during the test preparation phases; however, technical difficulties prevented its use during the integrated test. The Integrated ARS Test (IART) program built upon previous closed-door and open-door integrated testing conducted at MSFC between 1987 and 1992. It is the most advanced test of an integrated ARS conducted by NASA to demonstrate its end-to-end control and overall performance. IART test objectives, facility design, pretest analyses, test and control requirements, and test results are presented.

Experimental Control of Thermocapillary Convection in a Liquid Bridge

NASA Technical Reports Server (NTRS)

Petrov, Valery; Schatz, Michael F.; Muehlner, Kurt A.; VanHook, Stephen J.; McCormick, W. D.; Swift, Jack B.; Swinney, Harry L.

1996-01-01

We demonstrate the stabilization of an isolated unstable periodic orbit in a liquid bridge convection experiment. A model independent, nonlinear control algorithm uses temperature measurements near the liquid interface to compute control perturbations which are applied by a thermoelectric element. The algorithm employs a time series reconstruction of a nonlinear control surface in a high dimensional phase space to alter the system dynamics.

Translation of an Object Using Phase-Controlled Sound Sources in Acoustic Levitation

NASA Astrophysics Data System (ADS)

Matsui, Takayasu; Ohdaira, Etsuzo; Masuzawa, Nobuyoshi; Ide, Masao

1995-05-01

Acoustic levitation is used for positioning materials in the development of new materials in space where there is no gravity. This technique is applicable to materials for which electromagnetic force cannot be used. If the levitation point of the materials can be controlled freely in this application, possibilities of new applications will be extended. In this paper we report on an experimental study on controlling the levitation point of the object in an acoustic levitation system. The system fabricated and tested in this study has two sound sources with vibrating plates facing each other. Translation of the object can be achieved by controlling the phase of the energizing electrical signal for one of the sound sources. It was found that the levitation point can be moved smoothly in proportion to the phase difference between the vibrating plates.

A system for conducting igneous petrology experiments under controlled redox conditions in reduced gravity

NASA Technical Reports Server (NTRS)

Williams, R. J.

1986-01-01

The Space Shuttle and the planned Space Station will permit experimentation under conditions of reduced gravitational acceleration offering experimental petrologists the opportunity to study crystal growth, element distribution, and phase chemistry. In particular the confounding effects of macro and micro scale buoyancy-induced convection and crystal settling or floatation can be greatly reduced over those observed in experiments in the terrestrial laboratory. Also, for experiments in which detailed replication of the environment is important, the access to reduced gravity will permit a more complete simulation of processes that may have occurred on asteroids or in free space. A technique that was developed to control, measure, and manipulate oxygen fugacites with small quantities of gas which are recirculated over the sample is described. This system should be adaptable to reduced gravity space experiments requiring redox control. Experiments done conventionally and those done using this technique yield identical results done in a 1-g field.

Elimination of spiral waves in a locally connected chaotic neural network by a dynamic phase space constraint.

PubMed

Li, Yang; Oku, Makito; He, Guoguang; Aihara, Kazuyuki

2017-04-01

In this study, a method is proposed that eliminates spiral waves in a locally connected chaotic neural network (CNN) under some simplified conditions, using a dynamic phase space constraint (DPSC) as a control method. In this method, a control signal is constructed from the feedback internal states of the neurons to detect phase singularities based on their amplitude reduction, before modulating a threshold value to truncate the refractory internal states of the neurons and terminate the spirals. Simulations showed that with appropriate parameter settings, the network was directed from a spiral wave state into either a plane wave (PW) state or a synchronized oscillation (SO) state, where the control vanished automatically and left the original CNN model unaltered. Each type of state had a characteristic oscillation frequency, where spiral wave states had the highest, and the intra-control dynamics was dominated by low-frequency components, thereby indicating slow adjustments to the state variables. In addition, the PW-inducing and SO-inducing control processes were distinct, where the former generally had longer durations but smaller average proportions of affected neurons in the network. Furthermore, variations in the control parameter allowed partial selectivity of the control results, which were accompanied by modulation of the control processes. The results of this study broaden the applicability of DPSC to chaos control and they may also facilitate the utilization of locally connected CNNs in memory retrieval and the exploration of traveling wave dynamics in biological neural networks. Copyright © 2017 Elsevier Ltd. All rights reserved.

Lightweight High Efficiency Electric Motors for Space Applications

NASA Technical Reports Server (NTRS)

Robertson, Glen A.; Tyler, Tony R.; Piper, P. J.

2011-01-01

Lightweight high efficiency electric motors are needed across a wide range of space applications from - thrust vector actuator control for launch and flight applications to - general vehicle, base camp habitat and experiment control for various mechanisms to - robotics for various stationary and mobile space exploration missions. QM Power?s Parallel Path Magnetic Technology Motors have slowly proven themselves to be a leading motor technology in this area; winning a NASA Phase II for "Lightweight High Efficiency Electric Motors and Actuators for Low Temperature Mobility and Robotics Applications" a US Army Phase II SBIR for "Improved Robot Actuator Motors for Medical Applications", an NSF Phase II SBIR for "Novel Low-Cost Electric Motors for Variable Speed Applications" and a DOE SBIR Phase I for "High Efficiency Commercial Refrigeration Motors" Parallel Path Magnetic Technology obtains the benefits of using permanent magnets while minimizing the historical trade-offs/limitations found in conventional permanent magnet designs. The resulting devices are smaller, lower weight, lower cost and have higher efficiency than competitive permanent magnet and non-permanent magnet designs. QM Power?s motors have been extensively tested and successfully validated by multiple commercial and aerospace customers and partners as Boeing Research and Technology. Prototypes have been made between 0.1 and 10 HP. They are also in the process of scaling motors to over 100kW with their development partners. In this paper, Parallel Path Magnetic Technology Motors will be discussed; specifically addressing their higher efficiency, higher power density, lighter weight, smaller physical size, higher low end torque, wider power zone, cooler temperatures, and greater reliability with lower cost and significant environment benefit for the same peak output power compared to typically motors. A further discussion on the inherent redundancy of these motors for space applications will be provided.

The Role of Reminding in the Effects of Spaced Repetitions on Cued Recall: Sufficient but Not Necessary

ERIC Educational Resources Information Center

Wahlheim, Christopher N.; Maddox, Geoffrey B.; Jacoby, Larry L.

2014-01-01

Three experiments examined the role of study-phase retrieval (reminding) in the effects of spaced repetitions on cued recall. Remindings were brought under task control to evaluate their effects. Participants studied 2 lists of word pairs containing 3 item types: single items that appeared once in List 2, within-list repetitions that appeared…

106 17 Telemetry Standards Chapter 2

DTIC Science & Technology

2017-07-31

high frequency STC space -time code SOQPSK shaped offset quadrature phase shift keying UHF ultra- high frequency US&P United States...and Possessions VCO voltage-controlled oscillator VHF very- high frequency WCS Wireless Communication Service Telemetry Standards, RCC Standard...get interference. a. Telemetry Bands Air and space -to-ground telemetering is allocated in the ultra- high frequency (UHF) bands 1435 to 1535, 2200

Coronas-F Orbit Monitoring and Re-Entry Prediction

NASA Technical Reports Server (NTRS)

Ivanov, N. M.; Kolyuka, Yu. F.; Afanasieva, T. I.; Gridchina, T. A.

2007-01-01

Russian scientific satellite CORONAS-F was launched on July, 31, 2001. The object was inserted in near-circular orbit with the inclination 82.5deg and a mean altitude approx. 520 km. Due to the upper atmosphere drag CORONAS-F was permanently descended and as a result on December, 6, 2005 it has finished the earth-orbital flight, having lifetime in space approx. 4.5 years. The satellite structural features and its flight attitude control led to the significant variations of its ballistic coefficient during the flight. It was a cause of some specific difficulties in the fulfillment of the ballistic and navigation support of this space vehicle flight. Besides the main mission objective CORONAS-F also has been selected by the Inter-Agency Space Debris Coordination Committee (IADC) as a target object for the next regular international re-entry test campaign on a program of surveillance and re-entry prediction for the hazard space objects within their de-orbiting phases. Spacecraft (S/C) CORONAS-F kept its working state right up to the end of the flight - down to the atmosphere entry. This fact enabled to realization of the additional research experiments, concerning with an estimation of the atmospheric density within the low earth orbits (LEO) of the artificial satellites, and made possible to continue track the S/C during final phase of its flight by means of Russian regular command & tracking system, used for it control. Thus there appeared a unique possibility of using for tracking S/C at its de-orbiting phase not only passive radar facilities, belonging to the space surveillance systems and traditionally used for support of the IADC re-entry test campaigns, but also more precise active trajectory radio-tracking facilities from the ground control complex (GCC) applied for this object. Under the corresponding decision of the Russian side such capability of additional high-precise tracking control of the CORONAS-F flight in this period of time has been implemented. The organizing of the CORONAS-F ballistic and navigational support (BNS) and solving its main tasks (such as S/C orbit determination (OD) and its motion prediction and connected with them) both for regular mission stage and for additional flight program were realized by the group of specialists from the Mission Control Center (MCC). MCC was also assigned as a principal organization from the Russian side for participation in the 7th IADC re-entry test campaign on CORONAS-F. The CORONAS-F flight features and space environments circumstances during its flight as well as a methodology and technology of spacecraft ballistic and navigational support are given below. The BNS results for different phases of S/C flight, including the results of its re-entry predictions, obtained during the realization of the 7th IADC test campaign are submitted. The accuracy of space vehicle re-entry prediction and its dependence on various factors are analyzed in more details.

Design of the Heat Receiver for the U.S./Russia Solar Dynamic Power Joint Flight Demonstration

NASA Technical Reports Server (NTRS)

Strumpf, Hal J.; Krystkowiak, Christopher; Klucher, Beth A.

1996-01-01

A joint U.S./Russia program is being conducted to develop, fabricate, launch, and operate a solar dynamic demonstration system on Space Station Mir. The goal of the program is to demonstrate and confirm that solar dynamic power systems are viable for future space applications such as the International Space Station Alpha The major components of the system include a heat receiver, a closed Brayton cycle power conversion unit, a power conditioning and control unit, a concentrator, a radiator, a thermal control system, and a Space Shuttle Carrier. This paper discusses the design of the heat receiver component. The receiver comprises a cylindrical cavity, the walls of which are lined with a series of tubes running the length of the cavity. The engine working fluid, a mixture of xenon and helium, is heated by the concentrated sunlight incident on these tubes. The receiver incorporates integral thermal storage, using a eutectic mixture of lithium fluoride and calcium difluoride as the thermal storage solid-to-liquid phase change materiaL This thermal storage is required to enable power production during eclipse. The phase change material is contained in a series of individual containment canisters.

System technology analysis of aeroassisted orbital transfer vehicles: Moderate lift/drag (0.75-1.5). Volume 2: Supporting research and technology report, phase 1 and 2

NASA Technical Reports Server (NTRS)

1985-01-01

Technology payoffs of representative ground based (Phase 1) and space based (Phase 2) mid lift/drag ratio (L/D) aeroassisted orbit transfer vehicles (AOTV) were assessed and prioritized. The methodology employed to generate technology payoffs, the major payoffs identified, the urgency of the technology effort required, and the technology plans suggested are summarized for both study phases. Technology issues concerning aerodynamics, aerothermodynamics, thermal protection, propulsion, and guidance, navigation and control are addressed.

Generation of singular optical beams from fundamental Gaussian beam using Sagnac interferometer

NASA Astrophysics Data System (ADS)

Naik, Dinesh N.; Viswanathan, Nirmal K.

2016-09-01

We propose a simple free-space optics recipe for the controlled generation of optical vortex beams with a vortex dipole or a single charge vortex, using an inherently stable Sagnac interferometer. We investigate the role played by the amplitude and phase differences in generating higher-order Gaussian beams from the fundamental Gaussian mode. Our simulation results reveal how important the control of both the amplitude and the phase difference between superposing beams is to achieving optical vortex beams. The creation of a vortex dipole from null interference is unveiled through the introduction of a lateral shear and a radial phase difference between two out-of-phase Gaussian beams. A stable and high quality optical vortex beam, equivalent to the first-order Laguerre-Gaussian beam, is synthesized by coupling lateral shear with linear phase difference, introduced orthogonal to the shear between two out-of-phase Gaussian beams.

Template assisted strain tuning and phase stabilization in epitaxial BiFeO3 thin films

NASA Astrophysics Data System (ADS)

Saj Mohan M., M.; Ramadurai, Ranjith

2018-04-01

Strain engineering is a key to develop novel properties in functional materials. We report a strain mediated phase stabilization and epitaxial growth of bismuth ferrite(BiFeO3) thin films on LaAlO3 (LAO) substrates. The strain in the epitaxial layer is controlled by controlling the thickness of bottom electrode where the thickness of the BFO is kept constant. The thickness of La0.7Sr0.3MnO3(LSMO) template layer was optimized to grow completely strained tetragonal, tetragonal/rhombohedral mixed phase and fully relaxed rhombohedral phase of BFO layers. The results were confirmed with coupled-θ-2θ scan, and small area reciprocal space mapping. The piezoelectric d33 (˜ 45-48 pm/V) coefficient of the mixed phase was relatively larger than the strained tetragonal and relaxed rhombohedral phase for a given thickness.

Continuous-variable geometric phase and its manipulation for quantum computation in a superconducting circuit.

PubMed

Song, Chao; Zheng, Shi-Biao; Zhang, Pengfei; Xu, Kai; Zhang, Libo; Guo, Qiujiang; Liu, Wuxin; Xu, Da; Deng, Hui; Huang, Keqiang; Zheng, Dongning; Zhu, Xiaobo; Wang, H

2017-10-20

Geometric phase, associated with holonomy transformation in quantum state space, is an important quantum-mechanical effect. Besides fundamental interest, this effect has practical applications, among which geometric quantum computation is a paradigm, where quantum logic operations are realized through geometric phase manipulation that has some intrinsic noise-resilient advantages and may enable simplified implementation of multi-qubit gates compared to the dynamical approach. Here we report observation of a continuous-variable geometric phase and demonstrate a quantum gate protocol based on this phase in a superconducting circuit, where five qubits are controllably coupled to a resonator. Our geometric approach allows for one-step implementation of n-qubit controlled-phase gates, which represents a remarkable advantage compared to gate decomposition methods, where the number of required steps dramatically increases with n. Following this approach, we realize these gates with n up to 4, verifying the high efficiency of this geometric manipulation for quantum computation.

Preparation of pigments for space-stable thermal control coatings

NASA Technical Reports Server (NTRS)

Campbell, W. B.; Nychas, S. G.; Smith, R. G.

1971-01-01

Calculations of mixing conditions in the vapor reaction system established criteria for reactor design. Gas mixing was optimized by jet action and vapor phase production of zinc orthotitanate has been accomplished.

High-frequency ac power distribution in Space Station

NASA Technical Reports Server (NTRS)

Tsai, Fu-Sheng; Lee, Fred C. Y.

1990-01-01

A utility-type 20-kHz ac power distribution system for the Space Station, employing resonant power-conversion techniques, is presented. The system converts raw dc voltage from photovoltaic cells or three-phase LF ac voltage from a solar dynamic generator into a regulated 20-kHz ac voltage for distribution among various loads. The results of EASY5 computer simulations of the local and global performance show that the system has fast response and good transient behavior. The ac bus voltage is effectively regulated using the phase-control scheme, which is demonstrated with both line and load variations. The feasibility of paralleling the driver-module outputs is illustrated with the driver modules synchronized and sharing a common feedback loop. An HF sinusoidal ac voltage is generated in the three-phase ac input case, when the driver modules are phased 120 deg away from one another and their outputs are connected in series.

The effects of RCS jet firing on the isolated Orbiter and mated coast phases of the glide return to launch site maneuver at Mach number 6 (IA302B)

NASA Technical Reports Server (NTRS)

Garrett, L. V.; Buchanan, T. D.; Fryberger, P. E.

1988-01-01

An updated Space Shuttle aerodynamic data base was obtained in Tunnel B for two phases of the Glide Return to Launch Site (GRTLS) abort maneuver. One-and-a-quarter percent scale models of the Space Shuttle Orbiter and External Tank were used to measure the effects of various combinations of Reaction Control System (RCS) jet thrusters at Mach number 6. The angle-of-attack range for the isolated orbiter was -10 to 15 deg at sideslip angles from -5 to 10 deg during Phase 1 of testing. The angle-of-attack range for the mated orbiter and external tank was -5 to 15 deg with sideslip angles of -2 to 5 deg during Phase 2. The test was conducted at a unit Reynolds number of 0.75 million per foot.

Space Fed Subarray Synthesis Using Displaced Feed Location

NASA Astrophysics Data System (ADS)

Mailloux, Robert J.

2002-01-01

Wideband space-fed subarray systems are often proposed for large airborne or spaceborne scanning array applications. These systems allow the introduction of time delay devices at the subarray input terminals while using phase shifters in the array face. This can sometimes reduce the number of time delayed controls by an order of magnitude or more. The implementation of this technology has been slowed because the feed network, usually a Rotman Lens or Butler Matrix, is bulky, heavy and often has significant RF loss. In addition, the large lens aperture is necessarily filled with phase shifters, and so it introduces further loss, weight, and perhaps unacceptable phase shifter control power. These systems are currently viewed with increased interest because combination of low loss, low power MEMS phase shifters in the main aperture and solid state T/R modules in the feed might lead to large scanning arrays with much higher efficiency then previously realizable. Unfortunately, the conventional system design imposes an extremely large dynamic range requirement when used in the transmit mode, and requires very high output power from the T/R modules. This paper presents one possible solution to this problem using a modified feed geometry.

Development of magnetostrictive active members for control of space structures

NASA Technical Reports Server (NTRS)

Johnson, Bruce G.; Avakian, Kevin M.; Fenn, Ralph C.; Gaffney, Monique S.; Gerver, Michael J.; Hawkey, Timothy J.; Boudreau, Donald J.

1992-01-01

The goal of this Phase 2 Small Business Innovative Research (SBIR) project was to determine the technical feasibility of developing magnetostrictive active members for use as truss elements in space structures. Active members control elastic vibrations of truss-based space structures and integrate the functions of truss structure element, actively controlled actuator, and sensor. The active members must control structural motion to the sub-micron level and, for many proposed space applications, work at cryogenic temperatures. Under this program both room temperature and cryogenic temperature magnetostrictive active members were designed, fabricated, and tested. The results of these performance tests indicated that room temperature magnetostrictive actuators feature higher strain, stiffness, and force capability with lower amplifier requirements than similarly sized piezoelectric or electrostrictive active members, at the cost of higher mass. Two different cryogenic temperature magnetostrictive materials were tested at liquid nitrogen temperatures, both with larger strain capability than the room temperature magnetostrictive materials. The cryogenic active member development included the design and fabrication of a cryostat that allows operation of the cryogenic active member in a space structure testbed.

Development of magnetostrictive active members for control of space structures

NASA Astrophysics Data System (ADS)

Johnson, Bruce G.; Avakian, Kevin M.; Fenn, Ralph C.; Gaffney, Monique S.; Gerver, Michael J.; Hawkey, Timothy J.; Boudreau, Donald J.

1992-08-01

The goal of this Phase 2 Small Business Innovative Research (SBIR) project was to determine the technical feasibility of developing magnetostrictive active members for use as truss elements in space structures. Active members control elastic vibrations of truss-based space structures and integrate the functions of truss structure element, actively controlled actuator, and sensor. The active members must control structural motion to the sub-micron level and, for many proposed space applications, work at cryogenic temperatures. Under this program both room temperature and cryogenic temperature magnetostrictive active members were designed, fabricated, and tested. The results of these performance tests indicated that room temperature magnetostrictive actuators feature higher strain, stiffness, and force capability with lower amplifier requirements than similarly sized piezoelectric or electrostrictive active members, at the cost of higher mass. Two different cryogenic temperature magnetostrictive materials were tested at liquid nitrogen temperatures, both with larger strain capability than the room temperature magnetostrictive materials. The cryogenic active member development included the design and fabrication of a cryostat that allows operation of the cryogenic active member in a space structure testbed.

The eigenvalue problem in phase space.

PubMed

Cohen, Leon

2018-06-30

We formulate the standard quantum mechanical eigenvalue problem in quantum phase space. The equation obtained involves the c-function that corresponds to the quantum operator. We use the Wigner distribution for the phase space function. We argue that the phase space eigenvalue equation obtained has, in addition to the proper solutions, improper solutions. That is, solutions for which no wave function exists which could generate the distribution. We discuss the conditions for ascertaining whether a position momentum function is a proper phase space distribution. We call these conditions psi-representability conditions, and show that if these conditions are imposed, one extracts the correct phase space eigenfunctions. We also derive the phase space eigenvalue equation for arbitrary phase space distributions functions. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Phase transitions and their energetics in calcite biominerals

NASA Astrophysics Data System (ADS)

Gilbert, Pupa

2013-03-01

Biominerals include mollusk shells and the skeletons of algae, sponges, corals, sea urchins and most other animals. The function of biominerals are diverse: mechanical support, attack, defense, grinding, biting, and chewing, gravitational and magnetic field sensing, light focusing, and many others. The exquisite nanostructure of biominerals is directly controlled by the organisms, which have evolved to master the chemico-physical aspects of mineralization. By controlling the inorganic precursor nanoparticle size, packing, and phase transitions, organisms efficiently fill space, produce tough and hard structures, with micro- or macroscopic morphology optimized for their functions. Specifically, this talk will address two key questions: Q: How are the beautiful biomineral morphologies achieved? A: Using amorphous precursor phases, with phase transitions kinetically regulated (retarded) by proteins. Q: How do organisms co-orient their single-crystalline biominerals? A: Controlling the propagation of crystallinity one nanoparticle at a time, not atom-by-atom.

Evolutionary growth for Space Station Freedom electrical power system

NASA Technical Reports Server (NTRS)

Marshall, Matthew Fisk; Mclallin, Kerry; Zernic, Mike

1989-01-01

Over an operational lifetime of at least 30 yr, Space Station Freedom will encounter increased Space Station user requirements and advancing technologies. The Space Station electrical power system is designed with the flexibility to accommodate these emerging technologies and expert systems and is being designed with the necessary software hooks and hardware scars to accommodate increased growth demand. The electrical power system is planned to grow from the initial 75 kW up to 300 kW. The Phase 1 station will utilize photovoltaic arrays to produce the electrical power; however, for growth to 300 kW, solar dynamic power modules will be utilized. Pairs of 25 kW solar dynamic power modules will be added to the station to reach the power growth level. The addition of solar dynamic power in the growth phase places constraints in the initial Space Station systems such as guidance, navigation, and control, external thermal, truss structural stiffness, computational capabilities and storage, which must be planned-in, in order to facilitate the addition of the solar dynamic modules.

Urban greenspace for resilient city in the future: Case study of Yogyakarta City

NASA Astrophysics Data System (ADS)

Ni'mah, N. M.; Lenonb, S.

2017-06-01

The capacity of adaptation is essential elements towards urban resilience. One adaptation that can be done is to consider the provision of open space and public space in the city. Yogyakarta City development which focused on the built area and negates the open space has blurred the characteristics of the city. Efforts in increasing the availability of public space is one of the seven priorities of the programs included in the environmental and the utilization of space in Yogyakarta City. An understanding of the provision of public green open spaces in Yogyakarta is important because the products and processes that take place in a development will determine the successful implementation of the development plan. The objectives of this study are as follows: (1) to identify the provision green space in Yogyakarta City from the aspects of product and procedure; and (2) to identify the role of green space to build resilient city. This study is used descriptive qualitative approach with in-depth interview, literature review, and triangulation as the method for data collection. Yogyakarta has had instruments for public green open spaces provision called Masterplan Ruang Terbuka Hijau (RTH) Up-Scaling Yogyakarta 2013-2032 which govern the typologies and criteria for green open space development in the city.Public green open spaces development mechanism can be grouped into the planning phase, the utilization phase, and the control phase of each consisting of legal and regulatory aspects, institutional aspects, financial aspects, and technical aspects. The mechanism of green open space provision should regard the need of advocacy for “urban green commons” (UGCs) development as a systematic approach of collective-participatory for urban land management.

Design concepts and performance of NASA X-band (7162 MHz/8415 MHz) transponder for deep-space spacecraft applications

NASA Technical Reports Server (NTRS)

Mysoor, N. R.; Perret, J. D.; Kermode, A. W.

1991-01-01

The design concepts and measured performance characteristics are summarized of an X band (7162 MHz/8415 MHz) breadboard deep space transponder (DSP) for future spacecraft applications, with the first use scheduled for the Comet Rendezvous Asteroid Flyby (CRAF) and Cassini missions in 1995 and 1996, respectively. The DST consists of a double conversion, superheterodyne, automatic phase tracking receiver, and an X band (8415 MHz) exciter to drive redundant downlink power amplifiers. The receiver acquires and coherently phase tracks the modulated or unmodulated X band (7162 MHz) uplink carrier signal. The exciter phase modulates the X band (8415 MHz) downlink signal with composite telemetry and ranging signals. The receiver measured tracking threshold, automatic gain control, static phase error, and phase jitter characteristics of the breadboard DST are in good agreement with the expected performance. The measured results show a receiver tracking threshold of -158 dBm and a dynamic signal range of 88 dB.

James Webb Space Telescope Out of Chamber “A” on This Week @NASA – December 1, 2017

NASA Image and Video Library

2017-12-01

Our James Webb Space Telescope is now out of the historic Chamber A vacuum facility at our Johnson Space Center in Houston, after completing cryogenic testing designed to ensure the telescope works well in the cold, airless environment of space. Set to launch in 2019, Webb will study every phase in the history of our Universe, starting with the first luminous glows following the Big Bang. Also, NASA’s Next Mars Rover Mission, New Space Station Crew Trains for Launch, Update for Next SpaceX Launch to Space Station, Giant Black Hole Pair Photobombs Andromeda Galaxy, and Historic Apollo Mission Control Center Will Be Restored!

Explosive synchronization as a process of explosive percolation in dynamical phase space

PubMed Central

Zhang, Xiyun; Zou, Yong; Boccaletti, S.; Liu, Zonghua

2014-01-01

Explosive synchronization and explosive percolation are currently two independent phenomena occurring in complex networks, where the former takes place in dynamical phase space while the latter in configuration space. It has been revealed that the mechanism of EP can be explained by the Achlioptas process, where the formation of a giant component is controlled by a suppressive rule. We here introduce an equivalent suppressive rule for ES. Before the critical point of ES, the suppressive rule induces the presence of multiple, small sized, synchronized clusters, while inducing the abrupt formation of a giant cluster of synchronized oscillators at the critical coupling strength. We also show how the explosive character of ES degrades into a second-order phase transition when the suppressive rule is broken. These results suggest that our suppressive rule can be considered as a dynamical counterpart of the Achlioptas process, indicating that ES and EP can be unified into a same framework. PMID:24903808

WAKES: Wavelet Adaptive Kinetic Evolution Solvers

NASA Astrophysics Data System (ADS)

Mardirian, Marine; Afeyan, Bedros; Larson, David

2016-10-01

We are developing a general capability to adaptively solve phase space evolution equations mixing particle and continuum techniques in an adaptive manner. The multi-scale approach is achieved using wavelet decompositions which allow phase space density estimation to occur with scale dependent increased accuracy and variable time stepping. Possible improvements on the SFK method of Larson are discussed, including the use of multiresolution analysis based Richardson-Lucy Iteration, adaptive step size control in explicit vs implicit approaches. Examples will be shown with KEEN waves and KEEPN (Kinetic Electrostatic Electron Positron Nonlinear) waves, which are the pair plasma generalization of the former, and have a much richer span of dynamical behavior. WAKES techniques are well suited for the study of driven and released nonlinear, non-stationary, self-organized structures in phase space which have no fluid, limit nor a linear limit, and yet remain undamped and coherent well past the drive period. The work reported here is based on the Vlasov-Poisson model of plasma dynamics. Work supported by a Grant from the AFOSR.

Overview of Spontaneous Frequency Chirping in Confined Plasmas

NASA Astrophysics Data System (ADS)

Berk, Herbert

2012-10-01

Spontaneous rapid frequency chirping is now a commonly observed phenomenon in plasmas with an energetic particle component. These particles typically induce so called weak instabilities, where they excite background waves that the plasma can support such as shear Alfven waves. The explanation for this phenomenon attributes the frequency chirping to the formation of phase space structures in the form of holes and clumps. Normally a saturated mode, in the presence of background dissipation, would be expected decay after saturation as the background plasma absorbs the energy of the excited wave. However the phase space structures take an alternate route, and move to a regions of phase space that are lower energy states of the energetic particle distribution. Through the wave-resonant particle interaction, this movement is locked to the frequency observed by the wave. This phenomenon implies that alternate mechanisms for plasma relaxation need to be considered for plasma states new marginal stability. It is also possible that these chirping mechanisms can be used to advantage to externally control states of plasma.

Optical techniques to feed and control GaAs MMIC modules for phased array antenna applications

NASA Astrophysics Data System (ADS)

Bhasin, K. B.; Anzic, G.; Kunath, R. R.; Connolly, D. J.

A complex signal distribution system is required to feed and control GaAs monolithic microwave integrated circuits (MMICs) for phased array antenna applications above 20 GHz. Each MMIC module will require one or more RF lines, one or more bias voltage lines, and digital lines to provide a minimum of 10 bits of combined phase and gain control information. In a closely spaced array, the routing of these multiple lines presents difficult topology problems as well as a high probability of signal interference. To overcome GaAs MMIC phased array signal distribution problems optical fibers interconnected to monolithically integrated optical components with GaAs MMIC array elements are proposed as a solution. System architecture considerations using optical fibers are described. The analog and digital optical links to respectively feed and control MMIC elements are analyzed. It is concluded that a fiber optic network will reduce weight and complexity, and increase reliability and performance, but higher power will be required.

Optical techniques to feed and control GaAs MMIC modules for phased array antenna applications

NASA Technical Reports Server (NTRS)

Bhasin, K. B.; Anzic, G.; Kunath, R. R.; Connolly, D. J.

1986-01-01

A complex signal distribution system is required to feed and control GaAs monolithic microwave integrated circuits (MMICs) for phased array antenna applications above 20 GHz. Each MMIC module will require one or more RF lines, one or more bias voltage lines, and digital lines to provide a minimum of 10 bits of combined phase and gain control information. In a closely spaced array, the routing of these multiple lines presents difficult topology problems as well as a high probability of signal interference. To overcome GaAs MMIC phased array signal distribution problems optical fibers interconnected to monolithically integrated optical components with GaAs MMIC array elements are proposed as a solution. System architecture considerations using optical fibers are described. The analog and digital optical links to respectively feed and control MMIC elements are analyzed. It is concluded that a fiber optic network will reduce weight and complexity, and increase reliability and performance, but higher power will be required.

Phase-locked, erbium-fiber-laser-based frequency comb in the near infrared.

PubMed

Washburn, Brian R; Diddams, Scott A; Newbury, Nathan R; Nicholson, Jeffrey W; Yan, Man F; Jørgensen, Carsten G

2004-02-01

A phase-locked frequency comb in the near infrared is demonstrated with a mode-locked, erbium-doped, fiber laser whose output is amplified and spectrally broadened in dispersion-flattened, highly nonlinear optical fiber to span from 1100 to >2200 nm. The supercontinuum output comprises a frequency comb with a spacing set by the laser repetition rate and an offset by the carrier-envelope offset frequency, which is detected with the standard f-to-2f heterodyne technique. The comb spacing and offset frequency are phase locked to a stable rf signal with a fiber stretcher in the laser cavity and by control of the pump laser power, respectively. This infrared comb permits frequency metrology experiments in the near infrared in a compact, fiber-laser-based system.

Spacecraft applications of advanced global positioning system technology

NASA Technical Reports Server (NTRS)

1988-01-01

This is the final report on the Texas Instruments Incorporated (TI) simulations study of Spacecraft Application of Advanced Global Positioning System (GPS) Technology. This work was conducted for the NASA Johnson Space Center (JSC) under contract NAS9-17781. GPS, in addition to its baselined capability as a highly accurate spacecraft navigation system, can provide traffic control, attitude control, structural control, and uniform time base. In Phase 1 of this program, another contractor investigated the potential of GPS in these four areas and compared GPS to other techniques. This contract was for the Phase 2 effort, to study the performance of GPS for these spacecraft applications through computer simulations. TI had previously developed simulation programs for GPS differential navigation and attitude measurement. These programs were adapted for these specific spacecraft applications. In addition, TI has extensive expertise in the design and production of advanced GPS receivers, including space-qualified GPS receivers. We have drawn on this background to augment the simulation results in the system level overview, which is Section 2 of this report.

Existence and stability of limit cycles in control of anti-lock braking systems with two boundaries via perturbation theory

NASA Astrophysics Data System (ADS)

Köppen, Thomas; Küpper, Tassilo; Makarenkov, Oleg

2017-05-01

This paper presents a two-phase control logic for anti-lock braking systems (ABS). ABS are by now a standard component in every modern car, preventing the wheels from going into a lock situation where the wheels are fixed by the brake and the stopping distances are greatly prolonged. There are different approaches to such control logics. An ABS design proposed in recent literature controls the wheel's slip by creating stable limit cycles in the corresponding phase space. This design is modified via an analytical approach that is derived from perturbation theory. Simulation results document shorter braking distance compared to available tests in the literature.

Two-Phase Flow Research on the ISS for Thermal Control Applications

NASA Technical Reports Server (NTRS)

Motil, Brian J.

2013-01-01

With the era of full utilization of the ISS now upon us, this presentation will discuss some of the highest-priority areas for two-phase flow systems with thermal control applications. These priorities are guided by recommendations of a 2011 NRC Decadal Survey report, Recapturing a Future for Space Exploration, Life and Physical Sciences for a New Era as well as an internal NASA exercise in response to the NRC report conducted in early 2012. Many of these proposals are already in various stages of development, while others are still conceptual.

Griffiths-like phase in high TC perovskite La2FeReO6 prepared in a controlled reducing atmosphere

NASA Astrophysics Data System (ADS)

Kaipamagalath, Aswathi; Palakkal, Jasnamol P.; Varma, Manoj R.

2018-05-01

The perovskite La2FeReO6 is prepared by solid-state reaction method. Calcination was done in a controlled reducing atmosphere. The structure of the compound is found to be orthorhombic with Pbnm space group. From the DC magnetic studies, the transition temperature (TC) of La2FeReO6 is found to be at 729 K. A Griffiths-like phase is present in the material with ferromagnetic short-range correlations above TC up to the Griffiths temperature TG = 863 K.

Anharmonic quantum mechanical systems do not feature phase space trajectories

NASA Astrophysics Data System (ADS)

Oliva, Maxime; Kakofengitis, Dimitris; Steuernagel, Ole

2018-07-01

Phase space dynamics in classical mechanics is described by transport along trajectories. Anharmonic quantum mechanical systems do not allow for a trajectory-based description of their phase space dynamics. This invalidates some approaches to quantum phase space studies. We first demonstrate the absence of trajectories in general terms. We then give an explicit proof for all quantum phase space distributions with negative values: we show that the generation of coherences in anharmonic quantum mechanical systems is responsible for the occurrence of singularities in their phase space velocity fields, and vice versa. This explains numerical problems repeatedly reported in the literature, and provides deeper insight into the nature of quantum phase space dynamics.

The control unit of the near infrared spectrograph of the Euclid space mission: detailed design

NASA Astrophysics Data System (ADS)

Toledo-Moreo, Rafael; Colodro-Conde, Carlos; Gómez-Sáenz-de-Tejada, Jaime; Pérez-Lizán, David; Díaz-García, José Javier; Tubío-Araujo, Óscar; Raichs, Cayetano; Catalán, Jordi; Rebolo-López, Rafael

2016-07-01

The Near Infrared Spectrograph and Photometer (NISP) is one of the instruments on board the ESA EUCLID mission. The Universidad Politécnica de Cartagena and Instituto de Astrofísica de Canarias are responsible of the Instrument Control Unit of the NISP (NI-ICU) in the Euclid Consortium. The NI-ICU hardware is developed by CRISA (Airbus Defence and Space), and its main functions are: communication with the S/C and the Data Processing Unit, control of the Filter and Grism Wheels, control of the Calibration Unit and thermal control of the instrument. This paper presents the NI-ICU status of definition and design at the end of the detailed design phase.

Artificial neural network for the determination of Hubble Space Telescope aberration from stellar images

NASA Technical Reports Server (NTRS)

Barrett, Todd K.; Sandler, David G.

1993-01-01

An artificial-neural-network method, first developed for the measurement and control of atmospheric phase distortion, using stellar images, was used to estimate the optical aberration of the Hubble Space Telescope. A total of 26 estimates of distortion was obtained from 23 stellar images acquired at several secondary-mirror axial positions. The results were expressed as coefficients of eight orthogonal Zernike polynomials: focus through third-order spherical. For all modes other than spherical the measured aberration was small. The average spherical aberration of the estimates was -0.299 micron rms, which is in good agreement with predictions obtained when iterative phase-retrieval algorithms were used.

Spectral and temporal characterization of a fused-quartz-microresonator optical frequency comb

DOE Office of Scientific and Technical Information (OSTI.GOV)

Papp, Scott B.; Diddams, Scott A.

2011-11-15

We report on the fabrication of high-Q, fused-quartz microresonators and the parametric generation of a frequency comb with 36-GHz line spacing using them. We have characterized the intrinsic stability of the comb in both the time and frequency domains to assess its suitability for future precision metrology applications. Intensity autocorrelation measurements and line-by-line comb control reveal near-transform-limited picosecond pulse trains that are associated with good relative phase and amplitude stability of the comb lines. The comb's 36-GHz line spacing can be readily photodetected, which enables measurements of its intrinsic and absolute phase fluctuations.

Improving particle beam acceleration in plasmas

NASA Astrophysics Data System (ADS)

C. de Sousa, M.; L. Caldas, I.

2018-04-01

The dynamics of wave-particle interactions in magnetized plasmas restricts the wave amplitude to moderate values for particle beam acceleration from rest energy. We analyze how a perturbing invariant robust barrier modifies the phase space of the system and enlarges the wave amplitude interval for particle acceleration. For low values of the wave amplitude, the acceleration becomes effective for particles with initial energy close to the rest energy. For higher values of the wave amplitude, the robust barrier controls chaos in the system and restores the acceleration process. We also determine the best position for the perturbing barrier in phase space in order to increase the final energy of the particles.

Thermal Control of the Scientific Instrument Package in the Large Space Telescope

NASA Technical Reports Server (NTRS)

Hawks, K. H.

1972-01-01

The general thermal control system philosophy was to utilize passive control where feasible and to utilize active methods only where required for more accurate thermal control of the SIP components with narrow temperature tolerances. A thermal model of the SIP and a concept for cooling the SIP cameras are presented. The model and cooling concept have established a rationale for determining a Phase A baseline for SIP thermal control.

Mycological studies housed in the Apollo 16 microbial ecology evaluation device

NASA Technical Reports Server (NTRS)

Volz, P. A.

1973-01-01

Survival, death, and phenotype count have yielded variation in the number of fungi recovered from the controls and the flight exposed cuvettes during preliminary analysis of postflight first phase data. Also the preliminary analysis was indicative that fungi exposed to specific space flight conditions demonstrated variable survival rates and phenotype counts. Specific space flight conditions included full light space exposure for Chaetomium globosum, exposure at 300- and 254-nanometer wavelengths for Rhodotorula rubra, full light and 280-nanometer wavelength exposure for Trichophyton terrestre, and 254-nanometer wavelength exposure for Saccharomyces cerevisiae. In general, phenotype counts for flight cuvettes and survival rates for control cuvettes were higher compared with the remaining cuvettes.

Free-Piston Stirling Power Conversion Unit for Fission Surface Power, Phase I Final Report

NASA Technical Reports Server (NTRS)

Wood, J. Gary; Buffalino, Andrew; Holliday, Ezekiel; Penswick, Barry; Gedeon, David

2010-01-01

This report summarizes the design of a 12 kW dual opposed free-piston Stirling convertor and controller for potential future use in space missions. The convertor is heated via a pumped NaK loop and cooling is provided by a pumped water circuit. Convertor efficiency is projected at 27 percent (AC electrical out/heat in). The controller converts the AC electrical output to 120 Vdc and is projected at 91 percent efficiency. A mechanically simple arrangement, based on proven technology, was selected in which the piston is resonated almost entirely by the working space pressure swing, while the displacer is resonated by planar mechanical springs in the bounce space.

A position-dependent mass harmonic oscillator and deformed space

NASA Astrophysics Data System (ADS)

da Costa, Bruno G.; Borges, Ernesto P.

2018-04-01

We consider canonically conjugated generalized space and linear momentum operators x^ q and p^ q in quantum mechanics, associated with a generalized translation operator which produces infinitesimal deformed displacements controlled by a deformation parameter q. A canonical transformation (x ^ ,p ^ ) →(x^ q,p^ q ) leads the Hamiltonian of a position-dependent mass particle in usual space to another Hamiltonian of a particle with constant mass in a conservative force field of the deformed space. The equation of motion for the classical phase space (x, p) may be expressed in terms of the deformed (dual) q-derivative. We revisit the problem of a q-deformed oscillator in both classical and quantum formalisms. Particularly, this canonical transformation leads a particle with position-dependent mass in a harmonic potential to a particle with constant mass in a Morse potential. The trajectories in phase spaces (x, p) and (xq, pq) are analyzed for different values of the deformation parameter. Finally, we compare the results of the problem in classical and quantum formalisms through the principle of correspondence and the WKB approximation.

Quantum interference and control of the dynamic Franz-Keldysh effect: Generation and detection of terahertz space-charge fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Rui; Department of Physics and Astronomy, University of Kansas, Lawrence, Kansas 66045; Jacobs, Paul

2013-06-24

The Dynamic Franz Keldysh Effect (DFKE) is produced and controlled in bulk gallium arsenide by quantum interference without the aid of externally applied fields and is spatially and temporally resolved using ellipsometric pump-probe techniques. The {approx}3 THz internal driving field for the DFKE is a transient space-charge field that is associated with a critically damped coherent plasma oscillation produced by oppositely traveling ballistic electron and hole currents that are injected by two-color quantum interference techniques. The relative phase and polarization of the two pump pulses can be used to control the DFKE.

Quantum interference and control of the dynamic Franz-Keldysh effect: Generation and detection of terahertz space-charge fields

NASA Astrophysics Data System (ADS)

Wang, Rui; Jacobs, Paul; Zhao, Hui; Smirl, Arthur L.

2013-06-01

The Dynamic Franz Keldysh Effect (DFKE) is produced and controlled in bulk gallium arsenide by quantum interference without the aid of externally applied fields and is spatially and temporally resolved using ellipsometric pump-probe techniques. The ˜3 THz internal driving field for the DFKE is a transient space-charge field that is associated with a critically damped coherent plasma oscillation produced by oppositely traveling ballistic electron and hole currents that are injected by two-color quantum interference techniques. The relative phase and polarization of the two pump pulses can be used to control the DFKE.

CSI computer system/remote interface unit acceptance test results

NASA Technical Reports Server (NTRS)

Sparks, Dean W., Jr.

1992-01-01

The validation tests conducted on the Control/Structures Interaction (CSI) Computer System (CCS)/Remote Interface Unit (RIU) is discussed. The CCS/RIU consists of a commercially available, Langley Research Center (LaRC) programmed, space flight qualified computer and a flight data acquisition and filtering computer, developed at LaRC. The tests were performed in the Space Structures Research Laboratory (SSRL) and included open loop excitation, closed loop control, safing, RIU digital filtering, and RIU stand alone testing with the CSI Evolutionary Model (CEM) Phase-0 testbed. The test results indicated that the CCS/RIU system is comparable to ground based systems in performing real-time control-structure experiments.

High performance N2O4/amine elements: Blowapart

NASA Technical Reports Server (NTRS)

Lawver, B. R.

1977-01-01

The mechanisms controlling hypergolic propellant reactive stream separation (RRS) were studied and used to develop design criteria for injectors free from both steady state RSS and cyclic propellant stream separation. This was accomplished through the analysis of single element injectors using N204/MMH propellants; the injectors were representative of the space shuttle orbit maneuvering engine and space tug applications. A gas phase/surface reaction mechanism which controls RSS was identified. Injector design criteria were developed, which defined a critical chamber pressure for those operating conditions above which RSS occurs. It was found that the amount of interfacial surface area at impingement is controlled by injector hydraulics.

The Right Stuff: A Look Back at Three Decades of Flight Controller Training for Space Shuttle Mission Operations

NASA Technical Reports Server (NTRS)

Dittemore, Gary D.; Bertels, Christie

2010-01-01

This paper will summarize the thirty-year history of Space Shuttle operations from the perspective of training in NASA Johnson Space Center's Mission Control Center. It will focus on training and development of flight controllers and instructors, and how training practices have evolved over the years as flight experience was gained, new technologies developed, and programmatic needs changed. Operations of human spaceflight systems is extremely complex, therefore the training and certification of operations personnel is a critical piece of ensuring mission success. Mission Control Center (MCC-H), at the Lyndon B. Johnson Space Center, in Houston, Texas manages mission operations for the Space Shuttle Program, including the training and certification of the astronauts and flight control teams. This paper will give an overview of a flight control team s makeup and responsibilities during a flight, and details on how those teams are trained and certified. The training methodology for developing flight controllers has evolved significantly over the last thirty years, while the core goals and competencies have remained the same. In addition, the facilities and tools used in the control center have evolved. These changes have been driven by many factors including lessons learned, technology, shuttle accidents, shifts in risk posture, and generational differences. Flight controllers will share their experiences in training and operating the Space Shuttle throughout the Program s history. A primary method used for training Space Shuttle flight control teams is by running mission simulations of the orbit, ascent, and entry phases, to truly "train like you fly." The audience will learn what it is like to perform a simulation as a shuttle flight controller. Finally, we will reflect on the lessons learned in training for the shuttle program, and how those could be applied to future human spaceflight endeavors.

Microgravity Fluid Separation Physics: Experimental and Analytical Results

NASA Technical Reports Server (NTRS)

Shoemaker, J. Michael; Schrage, Dean S.

1997-01-01

Effective, low power, two-phase separation systems are vital for the cost-effective study and utilization of two-phase flow systems and flow physics of two-phase flows. The study of microgravity flows have the potential to reveal significant insight into the controlling mechanisms for the behavior of flows in both normal and reduced gravity environments. The microgravity environment results in a reduction in gravity induced buoyancy forces acting on the discrete phases. Thus, surface tension, viscous, and inertial forces exert an increased influence on the behavior of the flow as demonstrated by the axisymmetric flow patterns. Several space technology and operations groups have studied the flow behavior in reduced gravity since gas-liquid flows are encountered in several systems such as cabin humidity control, wastewater treatment, thermal management, and Rankine power systems.

Holonomic Quantum Control with Continuous Variable Systems.

PubMed

Albert, Victor V; Shu, Chi; Krastanov, Stefan; Shen, Chao; Liu, Ren-Bao; Yang, Zhen-Biao; Schoelkopf, Robert J; Mirrahimi, Mazyar; Devoret, Michel H; Jiang, Liang

2016-04-08

Universal computation of a quantum system consisting of superpositions of well-separated coherent states of multiple harmonic oscillators can be achieved by three families of adiabatic holonomic gates. The first gate consists of moving a coherent state around a closed path in phase space, resulting in a relative Berry phase between that state and the other states. The second gate consists of "colliding" two coherent states of the same oscillator, resulting in coherent population transfer between them. The third gate is an effective controlled-phase gate on coherent states of two different oscillators. Such gates should be realizable via reservoir engineering of systems that support tunable nonlinearities, such as trapped ions and circuit QED.

Optical arbitrary waveform generation based on multi-wavelength semiconductor fiber ring laser

NASA Astrophysics Data System (ADS)

Li, Peili; Ma, Xiaolu; Shi, Weihua; Xu, Enming

2017-09-01

A new scheme of generating optical arbitrary waveforms based on multi-wavelength semiconductor fiber ring laser (SFRL) is proposed. In this novel scheme, a wide and flat optical frequency comb (OFC) is provided directly by multi-wavelength SFRL, whose central frequency and comb spacing are tunable. OFC generation, de-multiplexing, amplitude and phase modulation, and multiplexing are implementing in an intensity and phase tunable comb filter, as induces the merits of high spectral coherence, satisfactory waveform control and low system loss. By using the mode couple theory and the transfer matrix method, the theoretical model of the scheme is established. The impacts of amplitude control, phase control, number of spectral line, and injection current of semiconductor optical amplifier (SOA) on the waveform similarity are studied using the theoretical model. The results show that, amplitude control and phase control error should be smaller than 1% and 0.64% respectively to achieve high similarity. The similarity of the waveform is improved with the increase of the number of spectral line. When the injection current of SOA is in a certain range, the optical arbitrary waveform reaches a high similarity.

The role of character positional frequency on Chinese word learning during natural reading.

PubMed

Liang, Feifei; Blythe, Hazel I; Bai, Xuejun; Yan, Guoli; Li, Xin; Zang, Chuanli; Liversedge, Simon P

2017-01-01

Readers' eye movements were recorded to examine the role of character positional frequency on Chinese lexical acquisition during reading and its possible modulation by word spacing. In Experiment 1, three types of pseudowords were constructed based on each character's positional frequency, providing congruent, incongruent, and no positional word segmentation information. Each pseudoword was embedded into two sets of sentences, for the learning and the test phases. In the learning phase, half the participants read sentences in word-spaced format, and half in unspaced format. In the test phase, all participants read sentences in unspaced format. The results showed an inhibitory effect of character positional frequency upon the efficiency of word learning when processing incongruent pseudowords both in the learning and test phase, and also showed facilitatory effect of word spacing in the learning phase, but not at test. Most importantly, these two characteristics exerted independent influences on word segmentation. In Experiment 2, three analogous types of pseudowords were created whilst controlling for orthographic neighborhood size. The results of the two experiments were consistent, except that the effect of character positional frequency was absent in the test phase in Experiment 2. We argue that the positional frequency of a word's constituent characters may influence the character-to-word assignment in a process that likely incorporates both lexical segmentation and identification.

AES Water Architecture Study Interim Results

NASA Technical Reports Server (NTRS)

Sarguisingh, Miriam J.

2012-01-01

The mission of the Advanced Exploration System (AES) Water Recovery Project (WRP) is to develop advanced water recovery systems in order to enable NASA human exploration missions beyond low earth orbit (LEO). The primary objective of the AES WRP is to develop water recovery technologies critical to near term missions beyond LEO. The secondary objective is to continue to advance mid-readiness level technologies to support future NASA missions. An effort is being undertaken to establish the architecture for the AES Water Recovery System (WRS) that meets both near and long term objectives. The resultant architecture will be used to guide future technical planning, establish a baseline development roadmap for technology infusion, and establish baseline assumptions for integrated ground and on-orbit environmental control and life support systems (ECLSS) definition. This study is being performed in three phases. Phase I of this study established the scope of the study through definition of the mission requirements and constraints, as well as indentifying all possible WRS configurations that meet the mission requirements. Phase II of this study focused on the near term space exploration objectives by establishing an ISS-derived reference schematic for long-duration (>180 day) in-space habitation. Phase III will focus on the long term space exploration objectives, trading the viable WRS configurations identified in Phase I to identify the ideal exploration WRS. The results of Phases I and II are discussed in this paper.

Artificial Gravity as a Multi-System Countermeasure: Effects on Cognitive Function

NASA Technical Reports Server (NTRS)

Sipes, Walter E.; Seaton, Kim; Slack, Kellely; Bowie, Kendra

2007-01-01

The Space Flight Cognitive Assessment Tool for Windows (WinSCAT) is a medical requirement on the International Space Station, and its purpose is to evaluate cognitive functioning after physical insult (e.g., head trauma, decompression sickness, exposure to toxic gases, medication side effects). The current objective is to assess cognitive functioning in a long duration space mission analog environment where Artificial Gravity is being applied as a countermeasure in a Bed Rest study. Methods: Fifteen male subjects (8 treatment and 7 control) who participated in 21 days of -6 degree head-down bed rest were assessed. Three practice and three baseline WinSCAT test sessions were administered during the pre-bed rest phase of study participation. During the bed rest phase, the WinSCAT test was scheduled every other day, following the centrifuge, for a total of 10 test sessions. (The treatment group received 60 minutes of centrifugation each day during the 21 days of bed rest. The control subjects were strapped to the centrifuge for the same length of time as the treatment group but were not spun.) During the post-bed rest (reconditioning) phase, the test was administered 4 times. Results: Individual differences were found both within and between the treatment and control groups. After controlling for the number of subjects in each group, the treatment group accounted for more off-nominal WinSCAT scores than the control group. Conclusions:There is some preliminary evidence that centrifuge spinning might negatively impact cognitive functioning. However, due to sample size limitations, it cannot be ascertained whether there were significant differences in cognitive performance between the treatment and control groups. If centrifugation had a negative effect on cognitive functioning, consistent decrements would be expected to be found with all treatment subjects across time. Individual differences in underlying cognitive ability and motivation level are other possible explanations for the results found in this study.

Cryogenic Two-Phase Flight Experiment: Results overview

NASA Technical Reports Server (NTRS)

Swanson, T.; Buchko, M.; Brennan, P.; Bello, M.; Stoyanof, M.

1995-01-01

This paper focuses on the flight results of the Cryogenic Two-Phase Flight Experiment (CRYOTP), which was a Hitchhiker based experiment that flew on the space shuttle Columbia in March of 1994 (STS-62). CRYOTP tested two new technologies for advanced cryogenic thermal control; the Space Heat Pipe (SHP), which was a constant conductance cryogenic heat pipe, and the Brilliant Eyes Thermal Storage Unit (BETSU), which was a cryogenic phase-change thermal storage device. These two devices were tested independently during the mission. Analysis of the flight data indicated that the SHP was unable to start in either of two attempts, for reasons related to the fluid charge, parasitic heat leaks, and cryocooler capacity. The BETSU test article was successfully operated with more than 250 hours of on-orbit testing including several cooldown cycles and 56 freeze/thaw cycles. Some degradation was observed with the five tactical cryocoolers used as thermal sinks, and one of the cryocoolers failed completely after 331 hours of operation. Post-flight analysis indicated that this problem was most likely due to failure of an electrical controller internal to the unit.

Controlling geometric phase optically in a single spin in diamond

NASA Astrophysics Data System (ADS)

Yale, Christopher G.

Geometric phase, or Berry phase, is an intriguing quantum mechanical phenomenon that arises from the cyclic evolution of a quantum state. Unlike dynamical phases, which rely on the time and energetics of the interaction, the geometric phase is determined solely by the geometry of the path travelled in parameter space. As such, it is robust to certain types of noise that preserve the area enclosed by the path, and shows promise for the development of fault-tolerant logic gates. Here, we demonstrate the optical control of geometric phase within a solid-state spin qubit, the nitrogen-vacancy center in diamond. Using stimulated Raman adiabatic passage (STIRAP), we evolve a coherent dark state along `tangerine slice' trajectories on the Bloch sphere and probe these paths through time-resolved state tomography. We then measure the accumulated geometric phase through phase reference to a third ground spin state. In addition, we examine the limits of this control due to adiabatic breakdown as well as the longer timescale effect of far-detuned optical fields. Finally, we intentionally introduce noise into the experimental control parameters, and measure the distributions of the resulting phases to probe the resilience of the phase to differing types of noise. We also examine this robustness as a function of traversal time as well as the noise amplitude. Through these studies, we demonstrate that geometric phase is a promising route toward fault-tolerant quantum information processing. This work is supported by the AFOSR, the NSF, and the German Research Foundation.

The space shuttle program from challenge to achievement: Space exploration rolling on tires

NASA Technical Reports Server (NTRS)

Felder, G. L.

1985-01-01

The Space Shuttle Transportation System is the first space program to employ the pneumatic tire as a part of space exploration. For aircraft tires, this program establishes new expectations as to what constitutes acceptable performance within a set of tough environmental and operational conditions. Tire design, stresses the usual low weight, high load, high speed, and excellent air retention features but at extremes well outside industry standards. Tires will continue to be an integral part of the Shuttle's landing phase in the immediate future since they afford a unique combination of directional control, braking traction, flotation and shock absorption not available by other systems.

Emergence of polysaccharide membrane walls through macro-space partitioning via interfacial instability.

PubMed

Okeyoshi, Kosuke; Okajima, Maiko K; Kaneko, Tatsuo

2017-07-21

Living organisms in drying environments build anisotropic structures and exhibit directionality through self-organization of biopolymers. However, the process of macro-scale assembly is still unknown. Here, we introduce a dissipative structure through a non-equilibrium process between hydration and deposition in the drying of a polysaccharide liquid crystalline solution. By controlling the geometries of the evaporation front in a limited space, multiple nuclei emerge to grow vertical membrane walls with macroscopic orientation. Notably, the membranes are formed through rational orientation of rod-like microassemblies along the dynamic three-phase contact line. Additionally, in the non-equilibrium state, a dissipative structure is ultimately immobilized as a macroscopically partitioned space by multiple vertical membranes. We foresee that such oriented membranes will be applicable to soft biomaterials with direction controllability, and the macroscopic space partitionings will aid in the understanding of the space recognition ability of natural products under drying environments.

Constraining neutron guide optimizations with phase-space considerations

NASA Astrophysics Data System (ADS)

Bertelsen, Mads; Lefmann, Kim

2016-09-01

We introduce a method named the Minimalist Principle that serves to reduce the parameter space for neutron guide optimization when the required beam divergence is limited. The reduced parameter space will restrict the optimization to guides with a minimal neutron intake that are still theoretically able to deliver the maximal possible performance. The geometrical constraints are derived using phase-space propagation from moderator to guide and from guide to sample, while assuming that the optimized guides will achieve perfect transport of the limited neutron intake. Guide systems optimized using these constraints are shown to provide performance close to guides optimized without any constraints, however the divergence received at the sample is limited to the desired interval, even when the neutron transport is not limited by the supermirrors used in the guide. As the constraints strongly limit the parameter space for the optimizer, two control parameters are introduced that can be used to adjust the selected subspace, effectively balancing between maximizing neutron transport and avoiding background from unnecessary neutrons. One parameter is needed to describe the expected focusing abilities of the guide to be optimized, going from perfectly focusing to no correlation between position and velocity. The second parameter controls neutron intake into the guide, so that one can select exactly how aggressively the background should be limited. We show examples of guides optimized using these constraints which demonstrates the higher signal to noise than conventional optimizations. Furthermore the parameter controlling neutron intake is explored which shows that the simulated optimal neutron intake is close to the analytically predicted, when assuming that the guide is dominated by multiple scattering events.

Light treatment for NASA shiftworkers.

PubMed

Stewart, K T; Hayes, B C; Eastman, C I

1995-04-01

Intense artificial light can phase-shift circadian rhythms and improve performance, sleep, and well-being during shiftwork simulations. In real shiftworkers, however, exposure to sunlight and other time cues may decrease the efficacy of light treatment, and occupational and family responsibilities may make it impractical. With these considerations in mind, we designed and tested light-treatment protocols for NASA personnel who worked on shifted schedules during two Space Shuttle missions. During the prelaunch week, treatment subjects self-administered light of approximately 10,000 lux at times of day that phase-delay circadian rhythms. Treatment continued during the missions and for several days afterward. No treatment was administered to subjects in the control group. Treatment subjects reported better sleep, performance, and physical and emotional well-being than control subjects and rated the treatment as highly effective for promoting adjustment to their work schedules. Light treatment is both feasible and beneficial for NASA personnel who must work on shifted schedules during Space Shuttle missions.

Phase-space networks of geometrically frustrated systems.

PubMed

Han, Yilong

2009-11-01

We illustrate a network approach to the phase-space study by using two geometrical frustration models: antiferromagnet on triangular lattice and square ice. Their highly degenerated ground states are mapped as discrete networks such that the quantitative network analysis can be applied to phase-space studies. The resulting phase spaces share some comon features and establish a class of complex networks with unique Gaussian spectral densities. Although phase-space networks are heterogeneously connected, the systems are still ergodic due to the random Poisson processes. This network approach can be generalized to phase spaces of some other complex systems.

Asymmetrical booster ascent guidance and control system design study. Volume 5: Space shuttle powered explicit guidance. [space shuttle development

NASA Technical Reports Server (NTRS)

Jaggers, R. F.

1974-01-01

An optimum powered explicit guidance algorithm capable of handling all space shuttle exoatospheric maneuvers is presented. The theoretical and practical basis for the currently baselined space shuttle powered flight guidance equations and logic is documented. Detailed flow diagrams for implementing the steering computations for all shuttle phases, including powered return to launch site (RTLS) abort, are also presented. Derivation of the powered RTLS algorithm is provided, as well as detailed flow diagrams for implementing the option. The flow diagrams and equations are compatible with the current powered flight documentation.

Engineering the Lidar In-space Technology Experiment

NASA Technical Reports Server (NTRS)

Couch, Richard H.; Moore, Chris L.

1992-01-01

The Lidar In-space Technology Experiment (LITE) is being developed by NASA for flight on the Space Shuttle in early 1994. A discussion of the NASA four-phase design process is followed by a short history of the experiment heritage. The instrument is then described at the subsystem level from an engineering point of view, with special emphasis on the laser and the receiver. Some aspects of designing for the space environment are discussed, as well as the importance of contamination control, and product assurance. Finally, the instrument integration and test process is described and the current status of the instrument development is given.

Phase 111A Crew Interface Specifications Development for Inflight Maintenance and Stowage Functions

NASA Technical Reports Server (NTRS)

Carl, John G.

1973-01-01

This report presents the findings and data products developed during the Phase IIIA Crew Interface Specification Study for Inflight Maintenance and Stowage Functions, performed by General Electric for the NASA, Johnson Space Center with a set of documentation that can be used as definitive guidelines to improve the present process of defining, controlling and managing flight crew interface requirements that are related to inflight maintenance (including assembly and servicing) and stowage functions. During the Phase IIIA contract period, the following data products were developed: 1) Projected NASA Crew Procedures/Flight Data File Development Process. 2) Inflight Maintenance Management Process Description. 3) Preliminary Draft, General Specification, Inflight Maintenance Management Requirements. 4) Inflight Maintenance Operational Process Description. 5) Preliminary Draft, General Specification, Inflight Maintenance Task and Support Requirements Analysis. 6) Suggested IFM Data Processing Reports for Logistics Management The above Inflight Maintenance data products have been developed during the Phase IIIA study after review of Space Shuttle Program Documentation, including the Level II Integrated Logistics Requirements and other DOD and NASA data relative to Payloads Accommodations and Satellite On-Orbit Servicing. These Inflight Maintenance data products were developed to be in consonance with Space Shuttle Program technical and management requirements.

JPL Advanced Thermal Control Technology Roadmap - 2008

NASA Technical Reports Server (NTRS)

Birur, Gaj

2008-01-01

This slide presentation reviews the status of thermal control technology at JPL and NASA.It shows the active spacecraft that are in vairous positions in the solar syatem, and beyond the solar system and the future missions that are under development. It then describes the challenges that the past missions posed with the thermal control systems. The various solutions that were implemented duirng the decades prior to 1990 are outlined. A review of hte thermal challenges of the future misions is also included. The exploration plan for Mars is then reviewed. The thermal challenges of the Mars Rovers are then outlined. Also the challenges of systems that would be able to be used in to explore Venus, and Titan are described. The future space telescope missions will also need thermal control technological advances. Included is a review of the thermal requirements for manned missions to the Moon. Both Active and passive technologies that have been used and will be used are reviewed. Those that are described are Mechanically Pumped Fluid Loops (MPFL), Loop Heat Pipes, an M3 Passive Cooler, Heat Siwtch for Space and Mars surface applications, phase change material (PCM) technology, a Gas Gap Actuateor using ZrNiH(x), the Planck Sorption Cooler (PCS), vapor compression -- Hybrid two phase loops, advanced pumps for two phase cooling loops, and heat pumps that are lightweight and energy efficient.

Multi-functional optical signal processing using optical spectrum control circuit

NASA Astrophysics Data System (ADS)

Hayashi, Shuhei; Ikeda, Tatsuhiko; Mizuno, Takayuki; Takahashi, Hiroshi; Tsuda, Hiroyuki

2015-02-01

Processing ultra-fast optical signals without optical/electronic conversion is in demand and time-to-space conversion has been proposed as an effective solution. We have designed and fabricated an arrayed-waveguide grating (AWG) based optical spectrum control circuit (OSCC) using silica planar lightwave circuit (PLC) technology. This device is composed of an AWG, tunable phase shifters and a mirror. The principle of signal processing is to spatially decompose the signal's frequency components by using the AWG. Then, the phase of each frequency component is controlled by the tunable phase shifters. Finally, the light is reflected back to the AWG by the mirror and synthesized. Amplitude of each frequency component can be controlled by distributing the power to high diffraction order light. The spectral controlling range of the OSCC is 100 GHz and its resolution is 1.67 GHz. This paper describes equipping the OSCC with optical coded division multiplex (OCDM) encoder/decoder functionality. The encoding principle is to apply certain phase patterns to the signal's frequency components and intentionally disperse the signal. The decoding principle is also to apply certain phase patterns to the frequency components at the receiving side. If the applied phase pattern compensates the intentional dispersion, the waveform is regenerated, but if the pattern is not appropriate, the waveform remains dispersed. We also propose an arbitrary filter function by exploiting the OSCC's amplitude and phase control attributes. For example, a filtered optical signal transmitted through multiple optical nodes that use the wavelength multiplexer/demultiplexer can be equalized.

Comparing State-Space Multivariable Controls to Multi-SISO Controls for Load Reduction of Drivetrain-Coupled Modes on Wind Turbines through Field-Testing: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fleming, P. A.; van Wingerden, J. W.; Wright, A. D.

2011-12-01

This paper presents the structure of an ongoing controller comparison experiment at NREL's National Wind Technology Center; the design process for the two controllers compared in this phase of the experiment, and initial comparison results obtained in field-testing. The intention of the study is to demonstrate the advantage of using modern multivariable methods for designing control systems for wind turbines versus conventional approaches. We will demonstrate the advantages through field-test results from experimental turbines located at the NWTC. At least two controllers are being developed side-by-side to meet an incrementally increasing number of turbine load-reduction objectives. The first, a multiplemore » single-input, single-output (m-SISO) approach, uses separately developed decoupled and classicially tuned controllers, which is, to the best of our knowledge, common practice in the wind industry. The remaining controllers are developed using state-space multiple-input and multiple-output (MIMO) techniques to explicity account for coupling between loops and to optimize given known frequency structures of the turbine and disturbance. In this first publication from the study, we present the structure of the ongoing controller comparison experiment, the design process for the two controllers compared in this phase, and initial comparison results obtained in field-testing.« less

Illustration of microphysical processes in Amazonian deep convective clouds in the gamma phase space: introduction and potential applications

NASA Astrophysics Data System (ADS)

Cecchini, Micael A.; Machado, Luiz A. T.; Wendisch, Manfred; Costa, Anja; Krämer, Martina; Andreae, Meinrat O.; Afchine, Armin; Albrecht, Rachel I.; Artaxo, Paulo; Borrmann, Stephan; Fütterer, Daniel; Klimach, Thomas; Mahnke, Christoph; Martin, Scot T.; Minikin, Andreas; Molleker, Sergej; Pardo, Lianet H.; Pöhlker, Christopher; Pöhlker, Mira L.; Pöschl, Ulrich; Rosenfeld, Daniel; Weinzierl, Bernadett

2017-12-01

The behavior of tropical clouds remains a major open scientific question, resulting in poor representation by models. One challenge is to realistically reproduce cloud droplet size distributions (DSDs) and their evolution over time and space. Many applications, not limited to models, use the gamma function to represent DSDs. However, even though the statistical characteristics of the gamma parameters have been widely studied, there is almost no study dedicated to understanding the phase space of this function and the associated physics. This phase space can be defined by the three parameters that define the DSD intercept, shape, and curvature. Gamma phase space may provide a common framework for parameterizations and intercomparisons. Here, we introduce the phase space approach and its characteristics, focusing on warm-phase microphysical cloud properties and the transition to the mixed-phase layer. We show that trajectories in this phase space can represent DSD evolution and can be related to growth processes. Condensational and collisional growth may be interpreted as pseudo-forces that induce displacements in opposite directions within the phase space. The actually observed movements in the phase space are a result of the combination of such pseudo-forces. Additionally, aerosol effects can be evaluated given their significant impact on DSDs. The DSDs associated with liquid droplets that favor cloud glaciation can be delimited in the phase space, which can help models to adequately predict the transition to the mixed phase. We also consider possible ways to constrain the DSD in two-moment bulk microphysics schemes, in which the relative dispersion parameter of the DSD can play a significant role. Overall, the gamma phase space approach can be an invaluable tool for studying cloud microphysical evolution and can be readily applied in many scenarios that rely on gamma DSDs.

76 FR 4228 - U.S.-India Bilateral Understanding: Revisions to U.S. Export and Reexport Controls Under the...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-25

... nonproliferation objectives and their desire to expand high technology cooperation and trade, the two leaders... cooperation in civil space, defense and other high- technology sectors. These steps include removal of Indian... Technology Control Regime, Australia Group, and Wassenaar Arrangement) in a phased manner, and to consult...

Optimal Recursive Digital Filters for Active Bending Stabilization

NASA Technical Reports Server (NTRS)

Orr, Jeb S.

2013-01-01

In the design of flight control systems for large flexible boosters, it is common practice to utilize active feedback control of the first lateral structural bending mode so as to suppress transients and reduce gust loading. Typically, active stabilization or phase stabilization is achieved by carefully shaping the loop transfer function in the frequency domain via the use of compensating filters combined with the frequency response characteristics of the nozzle/actuator system. In this paper we present a new approach for parameterizing and determining optimal low-order recursive linear digital filters so as to satisfy phase shaping constraints for bending and sloshing dynamics while simultaneously maximizing attenuation in other frequency bands of interest, e.g. near higher frequency parasitic structural modes. By parameterizing the filter directly in the z-plane with certain restrictions, the search space of candidate filter designs that satisfy the constraints is restricted to stable, minimum phase recursive low-pass filters with well-conditioned coefficients. Combined with optimal output feedback blending from multiple rate gyros, the present approach enables rapid and robust parametrization of autopilot bending filters to attain flight control performance objectives. Numerical results are presented that illustrate the application of the present technique to the development of rate gyro filters for an exploration-class multi-engined space launch vehicle.

Role and regulation of sigma S in general resistance conferred by low-shear simulated microgravity in Escherichia coli.

PubMed

Lynch, S V; Brodie, E L; Matin, A

2004-12-01

Life on Earth evolved in the presence of gravity, and thus it is of interest from the perspective of space exploration to determine if diminished gravity affects biological processes. Cultivation of Escherichia coli under low-shear simulated microgravity (SMG) conditions resulted in enhanced stress resistance in both exponential- and stationary-phase cells, making the latter superresistant. Given that microgravity of space and SMG also compromise human immune response, this phenomenon constitutes a potential threat to astronauts. As low-shear environments are encountered by pathogens on Earth as well, SMG-conferred resistance is also relevant to controlling infectious disease on this planet. The SMG effect resembles the general stress response on Earth, which makes bacteria resistant to multiple stresses; this response is sigma s dependent, irrespective of the growth phase. However, SMG-induced increased resistance was dependent on sigma s only in stationary phase, being independent of this sigma factor in exponential phase. sigma s concentration was some 30% lower in exponential-phase SMG cells than in normal gravity cells but was twofold higher in stationary-phase SMG cells. While SMG affected sigma s synthesis at all levels of control, the main reasons for the differential effect of this gravity condition on sigma s levels were that it rendered the sigma protein less stable in exponential phase and increased rpoS mRNA translational efficiency. Since sigma s regulatory processes are influenced by mRNA and protein-folding patterns, the data suggest that SMG may affect these configurations.

Temperature controlled evolution of monoclinic to super-tetragonal phase of epitaxial BiFeO3 thin films on La0.67Sr0.33MnO3 buffered SrTiO3 substrate

NASA Astrophysics Data System (ADS)

Singh, Anar; Kaifeng, Dong; Chen, Jing-Sheng

2018-03-01

Epitaxial BiFeO3 thin films of 130nm were deposited by pulsed laser deposition (PLD) technique on La0.67Sr0.33MnO3 buffered SrTiO3 (001) substrate at various temperatures under different ambient oxygen pressures. Reciprocal space mapping reveals that, with decreasing temperature and oxygen pressure, the broadly reported monoclinic phase (MA) of BiFeO3 thin film initially transforms to a tetragonal phase (T1) with c/a =1.05 (1) in a narrow girth of deposition condition and then to a super-tetragonal phase (T2) with giant c/a = 1.24 (1), as confirmed by reciprocal space mapping using high resolution x-ray diffraction. The surface morphology of the films reveals the island growth of the BiFeO3 films deposited at low temperatures. We propose that the transformation from monoclinic to the super-tetragonal phase is essentially due to the manifestation of excess local strain as a result of the island growth. This study offers a recipe to grow the super-tetragonal phase of BiFeO3, with giant c/a =1.24 (1) which exhibits exceptionally large ferroelectric polarization, on ferromagnetic layer La0.67Sr0.33MnO3. This phase of BiFeO3 can be utilized for the ferroelectric control of magnetism at the interface of BiFeO3 and La0.67Sr0.33MnO3.

Space-to-earth power transmission system

NASA Technical Reports Server (NTRS)

Stevens, G. H.; Schuh, R.

1976-01-01

A preliminary analysis was conducted to establish the requirements of a space-to-earth microwave power transmission system. The need for accurate phase control on the transmitter was established and methods for assessing the impact of power density and thermal constraints on system performance were demonstrated. Potential radio frequency interference was considered. The sensitivity of transmission system scale to variations in power source, transportation and orbital fabrication and assembly costs was also determined.

Solar power satellite system definition study. Volume 3: Reference system description, phase 1

NASA Technical Reports Server (NTRS)

1979-01-01

An analysis of the solar power satellite system is presented. The satellite solar energy conversion and microwave power transmission systems are discussed including the structure, power distribution, thermal control, and energy storage. Space construction and support systems are described including the work support facilities and construction equipment. An assessment of the space transportation system for the satellite and the ground receiving station is presented.

Astronaut Carl Meade mans pilots station during trajectory control exercise

NASA Image and Video Library

1994-09-12

STS064-22-024 (9-20 Sept. 1994) --- With a manual and lap top computer in front of him, astronaut Carl J. Meade, STS-64 mission specialist, supports operations with the Trajectory Control Sensor (TCS) aboard the Earth-orbiting space shuttle Discovery. For this exercise, Meade temporarily mans the pilot's station on the forward flight deck. The TCS is the work of a team of workers at NASA's Johnson Space Center. Data gathered during this flight was expected to prove valuable in designing and developing a sensor for use during the rendezvous and mating phases of orbiter missions to the space station. For this demonstration, the Shuttle Pointed Autonomous Research Tool for Astronomy 201 (SPARTAN 201) was used as the target vehicle during release and retrieval operations. Photo credit: NASA or National Aeronautics and Space Administration

Control of Dual-Opposed Stirling Convertors with Active Power Factor Correction Controllers

NASA Technical Reports Server (NTRS)

Regan, Timothy F.; Lewandowski, Edward J.; Schreiber, Jeffrey G.

2007-01-01

When using recently-developed active power factor correction (APFC) controllers in power systems comprised of dual-opposed free-piston Stirling convertors, a variety of configurations of the convertors and controller(s) can be considered, with configuration ultimately selected based on benefits of efficiency, reliability, and robust operation. The configuration must not only achieve stable control of the two convertors, but also synchronize and regulate motion of the pistons to minimize net dynamic forces. The NASA Glenn Research Center (GRC) System Dynamic Model (SDM) was used to study ten configurations of dual-opposed convertor systems. These configurations considered one controller with the alternators connected in series or in parallel, and two controllers with the alternators not connected (isolated). For the configurations where the alternators were not connected, several different approaches were evaluated to synchronize the two convertors. In addition, two thermodynamic configurations were considered: two convertors with isolated working spaces and convertors with a shared expansion space. Of the ten configurations studied, stable operating modes were found for four. Three of those four had a common expansion space. One stable configuration was found for the dual-opposed convertors with separate working spaces. That configuration required isochronous control of both convertors, and two APFC controllers were used to accomplish this. A frequency/phase control loop was necessary to allow each APFC controller to synchronize its associated convertor with a common frequency.

Control of Dual-Opposed Stirling Convertors with Active Power Factor Correction Controllers

NASA Technical Reports Server (NTRS)

Regan, Timothy F.; Lewandowski, Edward J.; Schreiber, Jeffrey G.

2006-01-01

When using recently-developed active power factor correction (APFC) controllers in power systems comprised of dual-opposed free-piston Stirling convertors, a variety of configurations of the convertors and controller(s) can be considered, with configuration ultimately selected based on benefits of efficiency, reliability, and robust operation. The configuration must not only achieve stable control of the two convertors, but also synchronize and regulate motion of the pistons to minimize net dynamic forces. The NASA Glenn Research Center (GRC) System Dynamic Model (SDM) was used to study ten configurations of dual-opposed convertor systems. These configurations considered one controller with the alternators connected in series or in parallel, and two controllers with the alternators not connected (isolated). For the configurations where the alternators were not connected, several different approaches were evaluated to synchronize the two convertors. In addition, two thermodynamic configurations were considered: two convertors with isolated working spaces and convertors with a shared expansion space. Of the ten configurations studied, stable operating modes were found for four. Three of those four had a common expansion space. One stable configuration was found for the dual-opposed convertors with separate working spaces. That configuration required isochronous control of both convertors, and two APFC controllers were used to accomplish this. A frequency/phase control loop was necessary to allow each APFC controller to synchronize its associated convertor with a common frequency.

Solar power satellite system definition study, volume 5. Phase 2: Final briefing

NASA Technical Reports Server (NTRS)

1979-01-01

A briefing outline of the definition study is presented. Topics discussed include: Solar Power Satellite (SPS) research and development, definition study, operations control, transportation, solid state SPS, pilot link analysis, and offshore space center.

Microgravity

NASA Image and Video Library

1994-03-04

Onboard Space Shuttle Columbia (STS-62) Pilot Andrew M. Allen looks over a procedures book in the midst of a 14-day mission. Allen is attired in a new thermally controlled undergarment. Allen wore the garment during the launch and entry phases of the flight.

Launch Vehicle Control Center Architectures

NASA Technical Reports Server (NTRS)

Watson, Michael D.; Epps, Amy; Woodruff, Van; Vachon, Michael Jacob; Monreal, Julio; Williams, Randall; McLaughlin, Tom

2014-01-01

This analysis is a survey of control center architectures of the NASA Space Launch System (SLS), United Launch Alliance (ULA) Atlas V and Delta IV, and the European Space Agency (ESA) Ariane 5. Each of these control center architectures have similarities in basic structure, and differences in functional distribution of responsibilities for the phases of operations: (a) Launch vehicles in the international community vary greatly in configuration and process; (b) Each launch site has a unique processing flow based on the specific configurations; (c) Launch and flight operations are managed through a set of control centers associated with each launch site, however the flight operations may be a different control center than the launch center; and (d) The engineering support centers are primarily located at the design center with a small engineering support team at the launch site.

Dynamic Testing of the NASA Hypersonic Project Combined Cycle Engine Testbed for Mode Transition Experiments

NASA Technical Reports Server (NTRS)

2011-01-01

NASA is interested in developing technology that leads to more routine, safe, and affordable access to space. Access to space using airbreathing propulsion systems has potential to meet these objectives based on Airbreathing Access to Space (AAS) system studies. To this end, the NASA Fundamental Aeronautics Program (FAP) Hypersonic Project is conducting fundamental research on a Turbine Based Combined Cycle (TBCC) propulsion system. The TBCC being studied considers a dual flow-path inlet system. One flow-path includes variable geometry to regulate airflow to a turbine engine cycle. The turbine cycle provides propulsion from take-off to supersonic flight. The second flow-path supports a dual-mode scramjet (DMSJ) cycle which would be initiated at supersonic speed to further accelerate the vehicle to hypersonic speed. For a TBCC propulsion system to accelerate a vehicle from supersonic to hypersonic speed, a critical enabling technology is the ability to safely and effectively transition from the turbine to the DMSJ-referred to as mode transition. To experimentally test methods of mode transition, a Combined Cycle Engine (CCE) Large-scale Inlet testbed was designed with two flow paths-a low speed flow-path sized for a turbine cycle and a high speed flow-path designed for a DMSJ. This testbed system is identified as the CCE Large-Scale Inlet for Mode Transition studies (CCE-LIMX). The test plan for the CCE-LIMX in the NASA Glenn Research Center (GRC) 10- by 10-ft Supersonic Wind Tunnel (10x10 SWT) is segmented into multiple phases. The first phase is a matrix of inlet characterization (IC) tests to evaluate the inlet performance and establish the mode transition schedule. The second phase is a matrix of dynamic system identification (SysID) experiments designed to support closed-loop control development at mode transition schedule operating points for the CCE-LIMX. The third phase includes a direct demonstration of controlled mode transition using a closed loop control system developed with the data obtained from the first two phases. Plans for a fourth phase include mode transition experiments with a turbine engine. This paper, focusing on the first two phases of experiments, presents developed operational and analysis tools for streamlined testing and data reduction procedures.

Autonomous Satellite Command and Control through the World Wide Web: Phase 3

NASA Technical Reports Server (NTRS)

Cantwell, Brian; Twiggs, Robert

1998-01-01

NASA's New Millenium Program (NMP) has identified a variety of revolutionary technologies that will support orders of magnitude improvements in the capabilities of spacecraft missions. This program's Autonomy team has focused on science and engineering automation technologies. In doing so, it has established a clear development roadmap specifying the experiments and demonstrations required to mature these technologies. The primary developmental thrusts of this roadmap are in the areas of remote agents, PI/operator interface, planning/scheduling fault management, and smart execution architectures. Phases 1 and 2 of the ASSET Project (previously known as the WebSat project) have focused on establishing World Wide Web-based commanding and telemetry services as an advanced means of interfacing a spacecraft system with the PI and operators. Current automated capabilities include Web-based command submission, limited contact scheduling, command list generation and transfer to the ground station, spacecraft support for demonstrations experiments, data transfer from the ground station back to the ASSET system, data archiving, and Web-based telemetry distribution. Phase 2 was finished in December 1996. During January-December 1997 work was commenced on Phase 3 of the ASSET Project. Phase 3 is the subject of this report. This phase permitted SSDL and its project partners to expand the ASSET system in a variety of ways. These added capabilities included the advancement of ground station capabilities, the adaptation of spacecraft on-board software, and the expansion of capabilities of the ASSET management algorithms. Specific goals of Phase 3 were: (1) Extend Web-based goal-level commanding for both the payload PI and the spacecraft engineer; (2) Support prioritized handling of multiple PIs as well as associated payload experimenters; (3) Expand the number and types of experiments supported by the ASSET system and its associated spacecraft; (4) Implement more advanced resource management, modeling and fault management capabilities that integrate the space and ground segments of the space system hardware; (5) Implement a beacon monitoring test; (6) Implement an experimental blackboard controller for space system management; (7) Further define typical ground station developments required for Internet-based remote control and for full system automation of the PI-to-spacecraft link. Each of those goals is examined in the next section. Significant sections of this report were also published as a conference paper.

Advanced Controller Developed for the Free-Piston Stirling Convertor

NASA Technical Reports Server (NTRS)

Gerber, Scott S.

2005-01-01

A free-piston Stirling power convertor is being considered as an advanced power-conversion technology for future NASA deep-space missions requiring long-life radioisotope power systems. The NASA Glenn Research Center has identified key areas where advanced technologies can enhance the capability of Stirling energy-conversion systems. One of these is power electronic controls. Current power-conversion technology for Glenn-tested Stirling systems consists of an engine-driven linear alternator generating an alternating-current voltage controlled by a tuning-capacitor-based alternating-current peak voltage load controller. The tuning capacitor keeps the internal alternator electromotive force (EMF) in phase with its respective current (i.e., passive power factor correction). The alternator EMF is related to the piston velocity, which must be kept in phase with the alternator current in order to achieve stable operation. This tuning capacitor, which adds volume and mass to the overall Stirling convertor, can be eliminated if the controller can actively drive the magnitude and phase of the alternator current.

Phase Space Exchange in Thick Wedge Absorbers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neuffer, David

The problem of phase space exchange in wedge absorbers with ionization cooling is discussed. The wedge absorber exchanges transverse and longitudinal phase space by introducing a position-dependent energy loss. In this paper we note that the wedges used with ionization cooling are relatively thick, so that single wedges cause relatively large changes in beam phase space. Calculation methods adapted to such “thick wedge” cases are presented, and beam phase-space transformations through such wedges are discussed.

Phase-space topography characterization of nonlinear ultrasound waveforms.

PubMed

Dehghan-Niri, Ehsan; Al-Beer, Helem

2018-03-01

Fundamental understanding of ultrasound interaction with material discontinuities having closed interfaces has many engineering applications such as nondestructive evaluation of defects like kissing bonds and cracks in critical structural and mechanical components. In this paper, to analyze the acoustic field nonlinearities due to defects with closed interfaces, the use of a common technique in nonlinear physics, based on a phase-space topography construction of ultrasound waveform, is proposed. The central idea is to complement the "time" and "frequency" domain analyses with the "phase-space" domain analysis of nonlinear ultrasound waveforms. A nonlinear time series method known as pseudo phase-space topography construction is used to construct equivalent phase-space portrait of measured ultrasound waveforms. Several nonlinear models are considered to numerically simulate nonlinear ultrasound waveforms. The phase-space response of the simulated waveforms is shown to provide different topographic information, while the frequency domain shows similar spectral behavior. Thus, model classification can be substantially enhanced in the phase-space domain. Experimental results on high strength aluminum samples show that the phase-space transformation provides a unique detection and classification capabilities. The Poincaré map of the phase-space domain is also used to better understand the nonlinear behavior of ultrasound waveforms. It is shown that the analysis of ultrasound nonlinearities is more convenient and informative in the phase-space domain than in the frequency domain. Copyright © 2017 Elsevier B.V. All rights reserved.

Gymnastics in Phase Space

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chao, Alexander Wu; /SLAC

2012-03-01

As accelerator technology advances, the requirements on accelerator beam quality become increasingly demanding. Facing these new demands, the topic of phase space gymnastics is becoming a new focus of accelerator physics R&D. In a phase space gymnastics, the beam's phase space distribution is manipulated and precision tailored to meet the required beam qualities. On the other hand, all realization of such gymnastics will have to obey accelerator physics principles as well as technological limitations. Recent examples of phase space gymnastics include Emittance exchanges, Phase space exchanges, Emittance partitioning, Seeded FELs and Microbunched beams. The emittance related topics of this listmore » are reviewed in this report. The accelerator physics basis, the optics design principles that provide these phase space manipulations, and the possible applications of these gymnastics, are discussed. This fascinating new field promises to be a powerful tool of the future.« less

The Precision Formation Flying Integrated Analysis Tool (PFFIAT)

NASA Technical Reports Server (NTRS)

Stoneking, Eric; Lyon, Richard G.; Sears, Edie; Lu, Victor

2004-01-01

Several space missions presently in the concept phase (e.g. Stellar Imager, Submillimeter Probe of Evolutionary Cosmic Structure, Terrestrial Planet Finder) plan to use multiple spacecraft flying in precise formation to synthesize unprecedently large aperture optical systems. These architectures present challenges to the attitude and position determination and control system; optical performance is directly coupled to spacecraft pointing with typical control requirements being on the scale of milliarcseconds and nanometers. To investigate control strategies, rejection of environmental disturbances, and sensor and actuator requirements, a capability is needed to model both the dynamical and optical behavior of such a distributed telescope system. This paper describes work ongoing at NASA Goddard Space Flight Center toward the integration of a set of optical analysis tools (Optical System Characterization and Analysis Research software, or OSCAR) with the Formation Flying Test Bed (FFTB). The resulting system is called the Precision Formation Flying Integrated Analysis Tool (PFFIAT), and it provides the capability to simulate closed-loop control of optical systems composed of elements mounted on multiple spacecraft. The attitude and translation spacecraft dynamics are simulated in the FFTB, including effects of the space environment (e.g. solar radiation pressure, differential orbital motion). The resulting optical configuration is then processed by OSCAR to determine an optical image. From this image, wavefront sensing (e.g. phase retrieval) techniques are being developed to derive attitude and position errors. These error signals will be fed back to the spacecraft control systems, completing the control loop. A simple case study is presented to demonstrate the present capabilities of the tool.

The Precision Formation Flying Integrated Analysis Tool (PFFIAT)

NASA Technical Reports Server (NTRS)

Stoneking, Eric; Lyon, Richard G.; Sears, Edie; Lu, Victor

2004-01-01

Several space missions presently in the concept phase (e.g. Stellar Imager, Sub- millimeter Probe of Evolutionary Cosmic Structure, Terrestrial Planet Finder) plan to use multiple spacecraft flying in precise formation to synthesize unprecedently large aperture optical systems. These architectures present challenges to the attitude and position determination and control system; optical performance is directly coupled to spacecraft pointing with typical control requirements being on the scale of milliarcseconds and nanometers. To investigate control strategies, rejection of environmental disturbances, and sensor and actuator requirements, a capability is needed to model both the dynamical and optical behavior of such a distributed telescope system. This paper describes work ongoing at NASA Goddard Space Flight Center toward the integration of a set of optical analysis tools (Optical System Characterization and Analysis Research software, or OSCAR) with the Formation J?lying Test Bed (FFTB). The resulting system is called the Precision Formation Flying Integrated Analysis Tool (PFFIAT), and it provides the capability to simulate closed-loop control of optical systems composed of elements mounted on multiple spacecraft. The attitude and translation spacecraft dynamics are simulated in the FFTB, including effects of the space environment (e.g. solar radiation pressure, differential orbital motion). The resulting optical configuration is then processed by OSCAR to determine an optical image. From this image, wavefront sensing (e.g. phase retrieval) techniques are being developed to derive attitude and position errors. These error signals will be fed back to the spacecraft control systems, completing the control loop. A simple case study is presented to demonstrate the present capabilities of the tool.

Reagentless chemiluminescence-based fiber optic sensors for regenerative life support in space

NASA Astrophysics Data System (ADS)

Atwater, James E.; Akse, James R.; DeHart, Jeffrey; Wheeler, Richard R., Jr.

1995-04-01

The initial feasibility demonstration of a reagentless chemiluminescence based fiber optic sensor technology for use in advanced regenerative life support applications in space and planetary outposts is described. The primary constraints for extraterrestrial deployment of any technology are compatibility with microgravity and hypogravity environments; minimal size, weight, and power consumption; and minimal use of expendables due to the great expense and difficulty inherent to resupply logistics. In the current research, we report the integration of solid state flow through modules for the production of aqueous phase reagents into an integrated system for the detection of important analytes by chemiluminescence, with fiber optic light transmission. By minimizing the need for resupply expendables, the use of solid phase modules makes complex chemical detection schemes practical. For the proof of concept, hydrogen peroxide and glucose were chosen as analytes. The reaction is catalyzed by glucose oxidase, an immobilized enzyme. The aqueous phase chemistry required for sensor operation is implemented using solid phase modules which adjust the pH of the influent stream, catalyze the oxidation of analyte, and provide the controlled addition of the luminophore to the flowing aqueous stream. Precise control of the pH has proven essential for the long-term sustained release of the luminophore. Electrocatalysis is achieved using a controlled potential across gold mesh and gold foil electrodes which undergo periodic polarity reversals. The development and initial characterization of performance of the reagentless fiber optic chemiluminescence sensors are presented in this paper.

MOEMs devices designed and tested for future astronomical instrumentation in space

NASA Astrophysics Data System (ADS)

Zamkotsian, Frédéric; Lanzoni, Patrick; Waldis, Severin; Noell, Wilfried; Conedera, Veronique; Fabre, Norbert; Viard, Thierry; Buisset, Christophe

2017-11-01

Next generation of astronomical instrumentation for space telescopes requires Micro-Opto-Electro- Mechanical Systems (MOEMS) with remote control capability and cryogenic operation. MOEMS devices have the capability to tailor the incoming light in terms of intensity and object selection with programmable slit masks, in terms of phase and wavefront control with micro-deformable mirrors, and finally in terms of spectrum with programmable diffraction gratings. Applications are multi-object spectroscopy (MOS), wavefront correction and programmable spectrographs. We are engaged since several years in the design, realization and characterization of MOEMS devices suited for astronomical instrumentation.

Integrated guidance, navigation and control verification plan primary flight system. [space shuttle avionics integration

NASA Technical Reports Server (NTRS)

1978-01-01

The verification process and requirements for the ascent guidance interfaces and the ascent integrated guidance, navigation and control system for the space shuttle orbiter are defined as well as portions of supporting systems which directly interface with the system. The ascent phase of verification covers the normal and ATO ascent through the final OMS-2 circularization burn (all of OPS-1), the AOA ascent through the OMS-1 burn, and the RTLS ascent through ET separation (all of MM 601). In addition, OPS translation verification is defined. Verification trees and roadmaps are given.

Nonlinear unitary transformations of space-variant polarized light fields from self-induced geometric-phase optical elements

NASA Astrophysics Data System (ADS)

Kravets, Nina; Brasselet, Etienne

2018-01-01

We propose to couple the optical orientational nonlinearities of liquid crystals with their ability to self-organize to tailor them to control space-variant-polarized optical fields in a nonlinear manner. Experimental demonstration is made using a liquid crystal light valve that behaves like a light-driven geometric phase optical element. We also unveil two original nonlinear optical processes, namely self-induced separability and nonseparability. These results contribute to the advancement of nonlinear singular optics that is still in its infancy despite 25 years of effort, which may foster the development of nonlinear protocols to manipulate high-dimensional optical information both in the classical and quantum regimes.

Space Station 20-kHz power management and distribution system

NASA Technical Reports Server (NTRS)

Hansen, Irving G.; Sundberg, Gale R.

1986-01-01

During the conceptual design phase a 20-kHz power distribution system was selected as the reference for the Space Station. The system is single-phase 400 VRMS, with a sinusoidal wave form. The initial user power level will be 75 kW with growth to 300 kW. The high-frequency system selection was based upon considerations of efficiency, weight, safety, ease of control, interface with computers, and ease of paralleling for growth. Each of these aspects will be discussed as well as the associated trade-offs involved. An advanced development program has been instituted to accelerate the maturation of the high-frequency system. Some technical aspects of the advanced development will be discussed.

Space station 20-kHz power management and distribution system

NASA Technical Reports Server (NTRS)

Hansen, I. G.; Sundberg, G. R.

1986-01-01

During the conceptual design phase a 20-kHz power distribution system was selected as the reference for the space station. The system is single-phase 400 VRMS, with a sinusoidal wave form. The initial user power level will be 75 kW with growth to 300 kW. The high-frequency system selection was based upon considerations of efficiency, weight, safety, ease of control, interface with computers, and ease of paralleling for growth. Each of these aspects will be discussed as well as the associated trade-offs involved. An advanced development program has been instituted to accelerate the maturation of the high-frequency system. Some technical aspects of the advanced development will be discussed.

Phase transitions in tumor growth: V what can be expected from cancer glycolytic oscillations?

NASA Astrophysics Data System (ADS)

Martin, R. R.; Montero, S.; Silva, E.; Bizzarri, M.; Cocho, G.; Mansilla, R.; Nieto-Villar, J. M.

2017-11-01

Experimental evidence confirms the existence of glycolytic oscillations in cancer, which allows it to self-organize in time and space far from thermodynamic equilibrium, and provides it with high robustness, complexity and adaptability. A kinetic model is proposed for HeLa tumor cells grown in hypoxia conditions. It shows oscillations in a wide range of parameters. Two control parameters (glucose and inorganic phosphate concentration) were varied to explore the phase space, showing also the presence of limit cycles and bifurcations. The complexity of the system was evaluated by focusing on stationary state stability and Lempel-Ziv complexity. Moreover, the calculated entropy production rate was demonstrated behaving as a Lyapunov function.

Lyapunov exponents and phase diagrams reveal multi-factorial control over TRAIL-induced apoptosis

PubMed Central

Aldridge, Bree B; Gaudet, Suzanne; Lauffenburger, Douglas A; Sorger, Peter K

2011-01-01

Receptor-mediated apoptosis proceeds via two pathways: one requiring only a cascade of initiator and effector caspases (type I behavior) and the second requiring an initiator–effector caspase cascade and mitochondrial outer membrane permeabilization (type II behavior). Here, we investigate factors controlling type I versus II phenotypes by performing Lyapunov exponent analysis of an ODE-based model of cell death. The resulting phase diagrams predict that the ratio of XIAP to pro-caspase-3 concentrations plays a key regulatory role: type I behavior predominates when the ratio is low and type II behavior when the ratio is high. Cell-to-cell variability in phenotype is observed when the ratio is close to the type I versus II boundary. By positioning multiple tumor cell lines on the phase diagram we confirm these predictions. We also extend phase space analysis to mutations affecting the rate of caspase-3 ubiquitylation by XIAP, predicting and showing that such mutations abolish all-or-none control over activation of effector caspases. Thus, phase diagrams derived from Lyapunov exponent analysis represent a means to study multi-factorial control over a complex biochemical pathway. PMID:22108795

Electrical 2π phase control of infrared light in a 350-nm footprint using graphene plasmons

NASA Astrophysics Data System (ADS)

Woessner, Achim; Gao, Yuanda; Torre, Iacopo; Lundeberg, Mark B.; Tan, Cheng; Watanabe, Kenji; Taniguchi, Takashi; Hillenbrand, Rainer; Hone, James; Polini, Marco; Koppens, Frank H. L.

2017-07-01

Modulating the amplitude and phase of light is at the heart of many applications such as wavefront shaping, transformation optics, phased arrays, modulators and sensors. Performing this task with high efficiency and small footprint is a formidable challenge. Metasurfaces and plasmonics are promising, but metals exhibit weak electro-optic effects. Two-dimensional materials, such as graphene, have shown great performance as modulators with small drive voltages. Here, we show a graphene plasmonic phase modulator that is capable of tuning the phase between 0 and 2π in situ. The device length of 350 nm is more than 30 times shorter than the 10.6 μm free-space wavelength. The modulation is achieved by spatially controlling the plasmon phase velocity in a device where the spatial carrier density profile is tunable. We provide a scattering theory for plasmons propagating through spatial density profiles. This work constitutes a first step towards two-dimensional transformation optics for ultracompact modulators and biosensing.

Phase-space evolution of x-ray coherence in phase-sensitive imaging.

PubMed

Wu, Xizeng; Liu, Hong

2008-08-01

X-ray coherence evolution in the imaging process plays a key role for x-ray phase-sensitive imaging. In this work we present a phase-space formulation for the phase-sensitive imaging. The theory is reformulated in terms of the cross-spectral density and associated Wigner distribution. The phase-space formulation enables an explicit and quantitative account of partial coherence effects on phase-sensitive imaging. The presented formulas for x-ray spectral density at the detector can be used for performing accurate phase retrieval and optimizing the phase-contrast visibility. The concept of phase-space shearing length derived from this phase-space formulation clarifies the spatial coherence requirement for phase-sensitive imaging with incoherent sources. The theory has been applied to x-ray Talbot interferometric imaging as well. The peak coherence condition derived reveals new insights into three-grating-based Talbot-interferometric imaging and gratings-based x-ray dark-field imaging.

Controllable phase transitions and novel selection rules in Josephson junctions with inherent orthogonality

NASA Astrophysics Data System (ADS)

Cheng, Qiang; Zhang, Kunhua; Ma, Hongyang

2018-03-01

We propose a new type of Josephson junction consisting of topologically nontrivial superconductors with inherent orthogonality and a ferromagnetic interface. It is found this type of junction can host rich ground states: 0 phase, π phase, 0 + π phase, φ0 phase and φ0 ± φ phase. Phase transitions can be controlled by changing the direction of the interfacial magnetization. Phase diagrams are presented in the orientation space. Novel selection rules for the lowest order current, sin ⁡ ϕ or cos ⁡ ϕ, of this kind of junction are derived. General conditions for the formation of various ground states are established, which possess guiding significance to the experimental design of required ground states for practical applications. We construct the succinct form of a Ginzburg-Landau type of free energy from the viewpoint of the interplay between topological superconductivity and ferromagnetism, which can immediately lead to the selection rules. The constructed terms are universally available to the topological Josephson junctions with or without inherent orthogonality reported recently. The spin supercurrent, its selection rules and their relations to the constructed energy are also investigated.

Ka-Band Multibeam Aperture Phased Array Being Developed

NASA Technical Reports Server (NTRS)

Reinhart, Richard C.; Kacpura, Thomas J.

2004-01-01

Phased-array antenna systems offer many advantages to low-Earth-orbiting satellite systems. Their large scan angles and multibeam capabilities allow for vibration-free, rapid beam scanning and graceful degradation operation for high rate downlink of data to users on the ground. Technology advancements continue to reduce the power, weight, and cost of these systems to make phased arrays a competitive alternative in comparison to the gimbled reflector system commonly used in science missions. One effort to reduce the cost of phased arrays is the development of a Ka-band multibeam aperture (MBA) phased array by Boeing Corporation under a contract jointly by the NASA Glenn Research Center and the Office of Naval Research. The objective is to develop and demonstrate a space-qualifiable dual-beam Ka-band (26.5-GHz) phased-array antenna. The goals are to advance the state of the art in Ka-band active phased-array antennas and to develop and demonstrate multibeam transmission technology compatible with spacecraft in low Earth orbit to reduce the cost of future missions by retiring certain development risks. The frequency chosen is suitable for space-to-space and space-to-ground communication links. The phased-array antenna has a radiation pattern designed by combining a set of individual radiating elements, optimized with the type of radiating elements used, their positions in space, and the amplitude and phase of the currents feeding the elements. This arrangement produces a directional radiation pattern that is proportional to the number of individual radiating elements. The arrays of interest here can scan the main beam electronically with a computerized algorithm. The antenna is constructed using electronic components with no mechanical parts, and the steering is performed electronically, without any resulting vibration. The speed of the scanning is limited primarily by the control electronics. The radiation performance degrades gracefully if a portion of the elements fail. The arrays can be constructed to conform to a mounting surface, and multibeam capability is integral to the design. However, there are challenges for mission designers using monolithic-microwave-integrated-circuit- (MMIC-) based arrays because of reduced power efficiency, higher costs, and certain system effects that result in link degradations. The multibeam aperture phased-array antenna development is attempting to address some of these issues, particularly manufacturing, costs, and system performance.

Hydrogen Maser Clock (HMC) Experiment

NASA Technical Reports Server (NTRS)

Vessot, Robert F. C.; Mattison, Edward M.

1997-01-01

The Hydrogen Maser Clock (HMC) project was originally conceived to fly on a reflight of the European Space Agency (ESA) free flying platform, the European Recoverable Carrier (EURECA) that had been launched into space and recovered by NASA's Space Transportation System (STS). A Phase B study for operation of HMC as one of the twelve EURECA payload components was begun in July 1991, and completed a year later. Phase C/D of HMC began in August 1992 and continued into early 1995. At that time ESA decided not to refly EURECA, leaving HMC without access to space. Approximately 80% of the flight support electronics are presently operating the HMC's physics package in a vacuum tank at the Smithsonian Astrophysical Observatory, and are now considered to be well-tested flight electronics. The package will continue to be operated until the end of 1997 or until a flight opportunity becomes avaiable. Appendices: letters and trip report; proceedings of the symposium on frequency standards and metrology; milli-celsius-stability thermal control for an orbiting frequency standard.

Development of a gravity-independent wastewater bioprocessor for advanced life support in space

NASA Technical Reports Server (NTRS)

Nashashibi-Rabah, Majda; Christodoulatos, Christos; Korfiatis, George P.; Janes, H. W. (Principal Investigator)

2005-01-01

Operation of aerobic biological reactors in space is controlled by a number of challenging constraints, mainly stemming from mass transfer limitations and phase separation. Immobilized-cell packed-bed bioreactors, specially designed to function in the absence of gravity, offer a viable solution for the treatment of gray water generated in space stations and spacecrafts. A novel gravity-independent wastewater biological processor, capable of carbon oxidation and nitrification of high-strength aqueous waste streams, is presented. The system, consisting of a fully saturated pressurized packed bed and a membrane oxygenation module attached to an external recirculation loop, operated continuously for over one year. The system attained high carbon oxidation efficiencies often exceeding 90% and ammonia oxidation reaching approximately 60%. The oxygen supply module relies on hydrophobic, nonporous, oxygen selective membranes, in a shell and tube configuration, for transferring oxygen to the packed bed, while keeping the gaseous and liquid phases separated. This reactor configuration and operating mode render the system gravity-independent and suitable for space applications.

Observation of quasiperiodic dynamics in a one-dimensional quantum walk of single photons in space

NASA Astrophysics Data System (ADS)

Xue, Peng; Qin, Hao; Tang, Bao; Sanders, Barry C.

2014-05-01

We realize the quasi-periodic dynamics of a quantum walker over 2.5 quasi-periods by realizing the walker as a single photon passing through a quantum-walk optical-interferometer network. We introduce fully controllable polarization-independent phase shifters in each optical path to realize arbitrary site-dependent phase shifts, and employ large clear-aperture beam displacers, while maintaining high-visibility interference, to enable 10 quantum-walk steps to be reached. By varying the half-wave-plate setting, we control the quantum-coin bias thereby observing a transition from quasi-periodic dynamics to ballistic diffusion.

Supervising Remote Humanoids Across Intermediate Time Delay

NASA Technical Reports Server (NTRS)

Hambuchen, Kimberly; Bluethmann, William; Goza, Michael; Ambrose, Robert; Rabe, Kenneth; Allan, Mark

2006-01-01

The President's Vision for Space Exploration, laid out in 2004, relies heavily upon robotic exploration of the lunar surface in early phases of the program. Prior to the arrival of astronauts on the lunar surface, these robots will be required to be controlled across space and time, posing a considerable challenge for traditional telepresence techniques. Because time delays will be measured in seconds, not minutes as is the case for Mars Exploration, uploading the plan for a day seems excessive. An approach for controlling humanoids under intermediate time delay is presented. This approach uses software running within a ground control cockpit to predict an immersed robot supervisor's motions which the remote humanoid autonomously executes. Initial results are presented.

GFAST Software Demonstration

NASA Image and Video Library

2017-03-17

NASA engineers and test directors gather in Firing Room 3 in the Launch Control Center at NASA's Kennedy Space Center in Florida, to watch a demonstration of the automated command and control software for the agency's Space Launch System (SLS) and Orion spacecraft. The software is called the Ground Launch Sequencer. It will be responsible for nearly all of the launch commit criteria during the final phases of launch countdowns. The Ground and Flight Application Software Team (GFAST) demonstrated the software. It was developed by the Command, Control and Communications team in the Ground Systems Development and Operations (GSDO) Program. GSDO is helping to prepare the center for the first test flight of Orion atop the SLS on Exploration Mission 1.

International Space Station United States Laboratory Module Water Recovery Management Subsystem Verification from Flight 5A to Stage ULF2

NASA Technical Reports Server (NTRS)

Williams, David E.; Labuda, Laura

2009-01-01

The International Space Station (ISS) Environmental Control and Life Support (ECLS) system comprises of seven subsystems: Atmosphere Control and Supply (ACS), Atmosphere Revitalization (AR), Fire Detection and Suppression (FDS), Temperature and Humidity Control (THC), Vacuum System (VS), Water Recovery and Management (WRM), and Waste Management (WM). This paper provides a summary of the nominal operation of the United States (U.S.) Laboratory Module WRM design and detailed element methodologies utilized during the Qualification phase of the U.S. Laboratory Module prior to launch and the Qualification of all of the modification kits added to it from Flight 5A up and including Stage ULF2.

Water Capture Device Signal Integration Board

NASA Technical Reports Server (NTRS)

Chamberlin, Kathryn J.; Hartnett, Andrew J.

2018-01-01

I am a junior in electrical engineering at Arizona State University, and this is my second internship at Johnson Space Center. I am an intern in the Command and Data Handling Branch of Avionics Division (EV2), my previous internship was also in EV2. During my previous internship I was assigned to the Water Capture Device payload, where I designed a prototype circuit board for the electronics system of the payload. For this internship, I have come back to the Water Capture Device project to further the work on the electronics design I completed previously. The Water Capture Device is an experimental payload to test the functionality of two different phase separators aboard the International Space Station (ISS). A phase separator sits downstream of a condensing heat exchanger (CHX) and separates the water from the air particles for environmental control on the ISS. With changing CHX technology, new phase separators are required. The goal of the project is to develop a test bed for the two phase separators to determine the best solution.

Multi-megawatt inverter/converter technology for space power applications

NASA Technical Reports Server (NTRS)

Myers, Ira T.; Baumann, Eric D.; Kraus, Robert; Hammoud, Ahmad N.

1992-01-01

Large power conditioning mass reductions will be required to enable megawatt power systems envisioned by the Strategic Defense Initiative, the Air Force, and NASA. Phase 1 of a proposed two phase interagency program has been completed to develop an 0.1 kg/kW DC/DC converter technology base for these future space applications. Three contractors, Hughes, General Electric (GE), and Maxwell were Phase 1 contractors in a competitive program to develop a megawatt lightweight DC/DC converter. Researchers at NASA Lewis Research Center and the University of Wisconsin also investigated technology in topology and control. All three contractors, as well as the University of Wisconsin, concluded at the end of the Phase 1 study, which included some critical laboratory work, that 0.1-kg/kW megawatt DC/DC converters can be built. This is an order of magnitude lower specific weight than is presently available. A brief description of each of the concepts used to meet the ambitious goals of this program are presented.

Equilibrium Phase Behavior of a Continuous-Space Microphase Former.

PubMed

Zhuang, Yuan; Zhang, Kai; Charbonneau, Patrick

2016-03-04

Periodic microphases universally emerge in systems for which short-range interparticle attraction is frustrated by long-range repulsion. The morphological richness of these phases makes them desirable material targets, but our relatively coarse understanding of even simple models hinders controlling their assembly. We report here the solution of the equilibrium phase behavior of a microscopic microphase former through specialized Monte Carlo simulations. The results for cluster crystal, cylindrical, double gyroid, and lamellar ordering qualitatively agree with a Landau-type free energy description and reveal the nontrivial interplay between cluster, gel, and microphase formation.

Decoupling control of a five-phase fault-tolerant permanent magnet motor by radial basis function neural network inverse

NASA Astrophysics Data System (ADS)

Chen, Qian; Liu, Guohai; Xu, Dezhi; Xu, Liang; Xu, Gaohong; Aamir, Nazir

2018-05-01

This paper proposes a new decoupled control for a five-phase in-wheel fault-tolerant permanent magnet (IW-FTPM) motor drive, in which radial basis function neural network inverse (RBF-NNI) and internal model control (IMC) are combined. The RBF-NNI system is introduced into original system to construct a pseudo-linear system, and IMC is used as a robust controller. Hence, the newly proposed control system incorporates the merits of the IMC and RBF-NNI methods. In order to verify the proposed strategy, an IW-FTPM motor drive is designed based on dSPACE real-time control platform. Then, the experimental results are offered to verify that the d-axis current and the rotor speed are successfully decoupled. Besides, the proposed motor drive exhibits strong robustness even under load torque disturbance.

Practical nonlinear method for detection of respiratory and cardiac dysfunction in human subjects

NASA Astrophysics Data System (ADS)

Katz, Richard A.; Lawee, Michael S.; Newman, Anthony K.; Weiss, J. Woodrow; Chandra, Shalabh; Grimm, Richard A.; Thomas, James D.

1995-12-01

This research applies novel nonlinear signal detection techniques in studies of human subjects with respiratory and cardiac diseases. One of the studies concerns a breathing disorder during sleep, a disease called Obstructive Sleep Apnea (OSA). In a second study we investigate a disease of the heart, Atrial Fibrillation (AF). The former study involves nonlinear processing of the time sequences of sleep apnea recordings (cardio-respirograms) collected from patients with known obstructive sleep apnea, and from a normal control. In the latter study, we apply similar nonlinear metrics to Doppler flow measurements obtained by transesophageal echocardiography (TEE). One of our metrics, the 'chaotic radius' is used for tracking the position of points in phase space relative to some reference position. A second metric, the 'differential radius' provides a measure of the separation rate of contiguous (evolving) points in phase space. A third metric, the 'chaotic frequency' gives angular position of the phase space orbit as a function of time. All are useful for identifying change of physiologic condition that is not always apparent using conventional methods.

Spherical Primary Optical Telescope (SPOT): An Architecture Demonstration for Cost-effective Large Space Telescopes

NASA Technical Reports Server (NTRS)

Feinberg, Lee D.; Hagopian, John; Budinoff, Jason; Dean, Bruce; Howard, Joe

2004-01-01

This paper summarizes efforts underway at the Goddard Space Flight Center to demonstrate a new type of space telescope architecture that builds on the rigid segmented telescope heritage of the James Webb Space Telescope but that solves several key challenges for future space telescopes. The architecture is based on a cost-effective segmented spherical primary mirror combined with a unique wavefront sensing and control system that allows for continuous phasing of the primary mirror. The segmented spherical primary allows for cost-effective 3-meter class (e.g., Midex and Discovery) missions as well as enables 30-meter telescope solutions that can be manufactured in a reasonable amount of time and for a reasonable amount of money. The continuous wavefront sensing and control architecture enables missions in low-earth-orbit and missions that do not require expensive stable structures and thermal control systems. For the 30-meter class applications, the paper discusses considerations for assembling and testing the telescopes in space. The paper also summarizes the scientific and technological roadmap for the architecture and also gives an overview of technology development, design studies, and testbed activities underway to demonstrate its feasibility.

Spherical Primary Optical Telescope (SPOT): An Architecture Demonstration for Cost-effective Large Space Telescopes

NASA Technical Reports Server (NTRS)

Feinberg, Lee; Hagopian, John; Budinoff, Jason; Dean, Bruce; Howard, Joe

2005-01-01

This paper summarizes efforts underway at the Goddard Space Flight Center to demonstrate a new type of space telescope architecture that builds on the rigid, segmented telescope heritage of the James Webb Space Telescope but that solves several key challenges for future space telescopes. The architecture is based on a cost-effective segmented spherical primary mirror combined with a unique wavefront sensing and control system that allows for continuous phasing of the primary mirror. The segmented spherical primary allows for cost-effective 3-meter class (eg, Midex and Discovery) missions as well as enables 30-meter telescope solutions that can be manufactured in a reasonable amount of time and for a reasonable amount of money. The continuous wavefront sensing and control architecture enables missions in low-earth-orbit and missions that do not require expensive stable structures and thermal control systems. For the 30-meter class applications, the paper discusses considerations for assembling and testing the telescopes in space. The paper also summarizes the scientific and technological roadmap for the architecture and also gives an overview of technology development, design studies, and testbed activities underway to demonstrate it s feasibility.

NASA and Russian Space Agency sign agreement for additional Space Shuttle/Mir missions

PubMed

Huff, W

1994-01-01

On December 16, 1993 NASA Administrator Daniel S. Goldin [correction of Golden] and the Russian Space Agency (RSA) director Yuri Koptev signed a protocol agreeing to up to 10 Shuttle flights to Mir with a total of 24 months time aboard Mir for U.S. astronants, a program of scientific and technological research, and the upgrade and extension of the Mir lifetime during the period 1995-1997. This is the first of a three-phase program in human spaceflight cooperation which may culminate in the construction of an international Space Station. This agreement starts joint development of spacecraft environmental control and life support systems and potential common space suit.

Coronagraphic Wavefront Control for the ATLAST-9.2m Telescope

NASA Technical Reports Server (NTRS)

Lyon, RIchard G.; Oegerle, William R.; Feinberg, Lee D.; Bolcar, Matthew R.; Dean, Bruce H.; Mosier, Gary E.; Postman, Marc

2010-01-01

The Advanced Technology for Large Aperture Space Telescope (ATLAST) concept was assessed as one of the NASA Astrophysics Strategic Mission Concepts (ASMC) studies. Herein we discuss the 9.2-meter diameter segmented aperture version and its wavefront sensing and control (WFSC) with regards to coronagraphic detection and spectroscopic characterization of exoplanets. The WFSC would consist of at least two levels of sensing and control: (i) an outer coarser level of sensing and control to phase and control the segments and secondary mirror in a manner similar to the James Webb Space Telescope but operating at higher temporal bandwidth, and (ii) an inner, coronagraphic instrument based, fine level of sensing and control for both amplitude and wavefront errors operating at higher temporal bandwidths. The outer loop would control rigid-body actuators on the primary and secondary mirrors while the inner loop would control one or more segmented deformable mirror to suppress the starlight within the coronagraphic field-of view. Herein we discuss the visible nulling coronagraph (VNC) and the requirements it levies on wavefront sensing and control and show the results of closed-loop simulations to assess performance and evaluate the trade space of system level stability versus control bandwidth.

Algorithms for Robust Identification and Control of Large Space Structures. Phase 1.

DTIC Science & Technology

1988-05-14

Variate Analysis," Proc. Amer. Control Conf., San Francisco, * pp. 445-451. LECTIQUE, J., Rault, A., Tessier, M., and Testud , J.L. (1978), "Multivariable...Rault, J.L. Testud , and J. Papon (1978), "Model Predictive Heuris- tic Control: Applications to Industrial Processes," Automatica, Vol. 14, pp. 413...Control ’. Conference, Minneapolis, MN, June. TESTUD , J.L. (1979), "Commande Numerique Multivariable du Ballon de Recupera- tion de Vapeur," Adersa/Gerbios

Results from an experiment that collected visible-light polarization data using unresolved imagery for classification of geosynchronous satellites

NASA Astrophysics Data System (ADS)

Speicher, Andy; Matin, Mohammad; Tippets, Roger; Chun, Francis; Strong, David

2015-05-01

In order to protect critical military and commercial space assets, the United States Space Surveillance Network must have the ability to positively identify and characterize all space objects. Unfortunately, positive identification and characterization of space objects is a manual and labor intensive process today since even large telescopes cannot provide resolved images of most space objects. The objective of this study was to collect and analyze visible-spectrum polarization data from unresolved images of geosynchronous satellites taken over various solar phase angles. Different collection geometries were used to evaluate the polarization contribution of solar arrays, thermal control materials, antennas, and the satellite bus as the solar phase angle changed. Since materials on space objects age due to the space environment, their polarization signature may change enough to allow discrimination of identical satellites launched at different times. Preliminary data suggests this optical signature may lead to positive identification or classification of each satellite by an automated process on a shorter timeline. The instrumentation used in this experiment was a United States Air Force Academy (USAFA) Department of Physics system that consists of a 20-inch Ritchey-Chrétien telescope and a dual focal plane optical train fed with a polarizing beam splitter. Following a rigorous calibration, polarization data was collected during two nights on eight geosynchronous satellites built by various manufacturers and launched several years apart. When Stokes parameters were plotted against time and solar phase angle, the data indicates that a polarization signature from unresolved images may have promise in classifying specific satellites.

Miniature X-band GaAs MMIC analog and bi-phase modulators for spaceborne communications applications

NASA Technical Reports Server (NTRS)

Mysoor, Narayan R.; Ali, Fazal

1992-01-01

The design concepts, analyses, and the development of GaAs monolithic microwave integrated circuit (MMIC) linear-phase and digital modulators for the next generation of spaceborne communications systems are summarized. The design approach uses a very compact lumped-element, quadrature hybrid, and MESFET-varactors to provide low-loss and well-controlled phase performance for deep-space transponder (DST) applications. The measured results of the MESFET-diode show a capacitance range of 2:1 under reverse bias, and a Q of 38 at 10 GHz. Three cascaded sections of hybrid-coupled reflection phase shifters have been modeled and simulations performed to provide an X-band (8415 +/- 50 MHz) DST phase modulator with +/-2.5 radians of peak phase deviation.

Optical Design of the Developmental Cryogenic Active Telescope Testbed (DCATT)

NASA Technical Reports Server (NTRS)

Davila, Pam; Wilson, Mark; Young, Eric W.; Lowman, Andrew E.; Redding, David C.

1997-01-01

In the summer of 1996, three Study teams developed conceptual designs and mission architectures for the Next Generation Space Telescope (NGST). Each group highlighted areas of technology development that need to be further advanced to meet the goals of the NGST mission. The most important areas for future study included: deployable structures, lightweight optics, cryogenic optics and mechanisms, passive cooling, and on-orbit closed loop wavefront sensing and control. NASA and industry are currently planning to develop a series of ground testbeds and validation flights to demonstrate many of these technologies. The Deployed Cryogenic Active Telescope Testbed (DCATT) is a system level testbed to be developed at Goddard Space Flight Center in three phases over an extended period of time. This testbed will combine an actively controlled telescope with the hardware and software elements of a closed loop wavefront sensing and control system to achieve diffraction limited imaging at 2 microns. We will present an overview of the system level requirements, a discussion of the optical design, and results of performance analyses for the Phase 1 ambient concept for DCATT,

Integration Method of Emphatic Motions and Adverbial Expressions with Scalar Parameters for Robotic Motion Coaching System

NASA Astrophysics Data System (ADS)

Okuno, Keisuke; Inamura, Tetsunari

A robotic coaching system can improve humans' learning performance of motions by intelligent usage of emphatic motions and adverbial expressions according to user reactions. In robotics, however, method to control both the motions and the expressions and how to bind them had not been adequately discussed from an engineering point of view. In this paper, we propose a method for controlling and binding emphatic motions and adverbial expressions by using two scalar parameters in a phase space. In the phase space, variety of motion patterns and verbal expressions are connected and can be expressed as static points. We show the feasibility of the proposing method through experiments of actual sport coaching tasks for beginners. From the results of participants' improvements in motion learning, we confirmed the feasibility of the methods to control and bind emphatic motions and adverbial expressions, as well as confirmed contribution of the emphatic motions and positive correlation of adverbial expressions for participants' improvements in motion learning. Based on the results, we introduce a hypothesis that individually optimized method for binding adverbial expression is required.

Other Challenges in the Development of the Orbiter Environmental Control Hardware

NASA Technical Reports Server (NTRS)

Gibb, J. W.; Mcintosh, M. E.; Heinrich, S. R.; Thomas, E.; Steele, M.; Schubert, F.; Koszenski, E. P.; Wynveen, R. A.; Murray, R. W.; Schelkopf, J. D.

1985-01-01

Development of the Space Shuttle orbiter environmental control and life support system (ECLSS) included the identification and resolution of several interesting problems in several systems. Some of these problems occurred late in the program, including the flight phase. Problems and solutions related to the ammonia boiler system (ABS), smoke detector, water/hydrogen separator, and waste collector system (WCS) are addressed.

Current Technology for Thermal Protection Systems

NASA Technical Reports Server (NTRS)

Scotti, Stephen J. (Compiler)

1992-01-01

Interest in thermal protection systems for high-speed vehicles is increasing because of the stringent requirements of such new projects as the Space Exploration Initiative, the National Aero-Space Plane, and the High-Speed Civil Transport, as well as the needs for improved capabilities in existing thermal protection systems in the Space Shuttle and in turbojet engines. This selection of 13 papers from NASA and industry summarizes the history and operational experience of thermal protection systems utilized in the national space program to date, and also covers recent development efforts in thermal insulation, refractory materials and coatings, actively cooled structures, and two-phase thermal control systems.

System analysis study of space platform and station accommodations for life sciences research facilities. Volume 2: Study results. Appendix E: Work breakdown structure and dictionary

NASA Technical Reports Server (NTRS)

Wiley, Lowell F.

1985-01-01

A work breakdown structure for the Space Station Life Sciences Research Facility (LSRF) is presented up to level 5. The purpose is to provide the framework for task planning and control and to serve as a basis for budgeting, task assignment, cost collection and report, and contractual performance measurement and tracking of the Full Scale Development Phase tasks.

Risk Assessment During the Final Phase of an Uncontrolled Re-Entry

NASA Astrophysics Data System (ADS)

Gaudel, A.; Hourtolle, C.; Goester, J. F.; Fuentes, N.

2013-09-01

As French National Space Agency, CNES is empowered to monitor compliance with technical regulations of the French Space Operation Act, FSOA, and to take all necessary measures to ensure the safety of people, property, public health and environment for all space operations involving French responsibility at international level.Therefore, CNES developed ELECTRA that calculates the risk for ground population involved in three types of events: rocket launching, controlled re-entry and uncontrolled re-entry. For the first two cases, ELECTRA takes into account degraded cases due to a premature stop of propulsion.Major evolutions were implemented recently on ELECTRA to meet new users' requirements, like the risk assessment during the final phase of uncontrolled re-entry, that can be combined with the computed risk for each country involved by impacts.The purpose of this paper is to provide an overview of the ELECTRA method and main functionalities, and then to highlight these recent improvements.

Space Weathering on 4 Vesta: Processes and Products

NASA Technical Reports Server (NTRS)

Pieters, C. M.; Blewett, D. T.; Gaffey, M.; Mittlefehldt, D. W.; De Sanctis, M. C.; Reddy, V.; Nathues, A.; Denevi, B. W.; Li, J. Y.; McCord, T. B.;

Free-space laser communication technologies IV; Proceedings of the 4th Conference, Los Angeles, CA, Jan. 23, 24, 1992

NASA Technical Reports Server (NTRS)

Begley, David L. (Editor); Seery, Bernard D. (Editor)

1992-01-01

Papers included in this volume are grouped under topics of receivers; laser transmitters; components; system analysis, performance, and applications; and beam control (pointing, acquisition, and tracking). Papers are presented on an experimental determination of power penalty contributions in an optical Costas-type phase-locked loop receiver, a resonant laser receiver for free-space laser communications, a simple low-loss technique for frequency-locking lasers, direct phase modulation of laser diodes, and a silex beacon. Particular attention is given to experimental results on an optical array antenna for nonmechanical beam steering, a potassium Faraday anomalous dispersion optical filter, a 100-Mbps resonant cavity phase modulator for coherent optical communications, a numerical simulation of a 325-Mbit/s QPPM optical communication system, design options for an optical multiple-access data relay terminal, CCD-based optical tracking loop design trades, and an analysis of a spatial-tracking subsystem for optical communications.

Lightweight Motorized Valve

NASA Technical Reports Server (NTRS)

Gonzalez, R.; Vandewalle, J.

1986-01-01

Redesigned actuator assembly weighs 50 percent less. Isolator valve operated by ac motor instead of usual dc solenoid. Valve weighs only 3 lb (1.4 kg). New valve functions with either two-phase or three-phase power. Developed for isolating fluids in propellant tanks, manifolds, and interconnecting lines of Space Shuttle reaction control and orbital maneuvering subsystems, valve suited to applications in which leakage must be kept to minimum at high pressure differences - in petroleum and chemical processing.

Oscillatory cellular patterns in three-dimensional directional solidification

NASA Astrophysics Data System (ADS)

Tourret, D.; Debierre, J.-M.; Song, Y.; Mota, F. L.; Bergeon, N.; Guérin, R.; Trivedi, R.; Billia, B.; Karma, A.

2015-10-01

We present a phase-field study of oscillatory breathing modes observed during the solidification of three-dimensional cellular arrays in microgravity. Directional solidification experiments conducted onboard the International Space Station have allowed us to observe spatially extended homogeneous arrays of cells and dendrites while minimizing the amount of gravity-induced convection in the liquid. In situ observations of transparent alloys have revealed the existence, over a narrow range of control parameters, of oscillations in cellular arrays with a period ranging from about 25 to 125 min. Cellular patterns are spatially disordered, and the oscillations of individual cells are spatiotemporally uncorrelated at long distance. However, in regions displaying short-range spatial ordering, groups of cells can synchronize into oscillatory breathing modes. Quantitative phase-field simulations show that the oscillatory behavior of cells in this regime is linked to a stability limit of the spacing in hexagonal cellular array structures. For relatively high cellular front undercooling (i.e., low growth velocity or high thermal gradient), a gap appears in the otherwise continuous range of stable array spacings. Close to this gap, a sustained oscillatory regime appears with a period that compares quantitatively well with experiment. For control parameters where this gap exists, oscillations typically occur for spacings at the edge of the gap. However, after a change of growth conditions, oscillations can also occur for nearby values of control parameters where this gap just closes and a continuous range of spacings exists. In addition, sustained oscillations at to the opening of this stable gap exhibit a slow periodic modulation of the phase-shift among cells with a slower period of several hours. While long-range coherence of breathing modes can be achieved in simulations for a perfect spatial arrangement of cells as initial condition, global disorder is observed in both three-dimensional experiments and simulations from realistic noisy initial conditions. In the latter case, erratic tip-splitting events promoted by large-amplitude oscillations contribute to maintaining the long-range array disorder, unlike in thin-sample experiments where long-range coherence of oscillations is experimentally observable.

Oscillatory cellular patterns in three-dimensional directional solidification

DOE PAGES

Tourret, D.; Debierre, J. -M.; Song, Y.; ...

2015-09-11

We present a phase-field study of oscillatory breathing modes observed during the solidification of three-dimensional cellular arrays in micro-gravity. Directional solidification experiments conducted onboard the International Space Station have allowed for the first time to observe spatially extended homogeneous arrays of cells and dendrites while minimizing the amount of gravity-induced convection in the liquid. In situ observations of transparent alloys have revealed the existence, over a narrow range of control parameters, of oscillations in cellular arrays with a period ranging from about 25 to 125 minutes. Cellular patterns are spatially disordered, and the oscillations of individual cells are spatiotemporally uncorrelatedmore » at long distance. However, in regions displaying short-range spatial ordering, groups of cells can synchronize into oscillatory breathing modes. Quantitative phase-field simulations show that the oscillatory behavior of cells in this regime is linked to a stability limit of the spacing in hexagonal cellular array structures. For relatively high cellular front undercooling (\\ie low growth velocity or high thermal gradient), a gap appears in the otherwise continuous range of stable array spacings. Close to this gap, a sustained oscillatory regime appears with a period that compares quantitatively well with experiment. For control parameters where this gap exist, oscillations typically occur for spacings at the edge of the gap. However, after a change of growth conditions, oscillations can also occur for nearby values of control parameters where this gap just closes and a continuous range of spacings exists. In addition, sustained oscillations at to the opening of this stable gap exhibit a slow periodic modulation of the phase-shift among cells with a slower period of several hours. While long-range coherence of breathing modes can be achieved in simulations for a perfect spatial arrangement of cells as initial condition, global disorder is observed in both three-dimensional experiments and simulations from realistic noisy initial conditions. The, erratic tip splitting events promoted by large amplitude oscillations contribute to maintaining the long-range array disorder, unlike in thin sample experiments where long-range coherence of oscillations is experimentally observable.« less

Oscillatory cellular patterns in three-dimensional directional solidification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tourret, D.; Debierre, J. -M.; Song, Y.

We present a phase-field study of oscillatory breathing modes observed during the solidification of three-dimensional cellular arrays in micro-gravity. Directional solidification experiments conducted onboard the International Space Station have allowed for the first time to observe spatially extended homogeneous arrays of cells and dendrites while minimizing the amount of gravity-induced convection in the liquid. In situ observations of transparent alloys have revealed the existence, over a narrow range of control parameters, of oscillations in cellular arrays with a period ranging from about 25 to 125 minutes. Cellular patterns are spatially disordered, and the oscillations of individual cells are spatiotemporally uncorrelatedmore » at long distance. However, in regions displaying short-range spatial ordering, groups of cells can synchronize into oscillatory breathing modes. Quantitative phase-field simulations show that the oscillatory behavior of cells in this regime is linked to a stability limit of the spacing in hexagonal cellular array structures. For relatively high cellular front undercooling (\\ie low growth velocity or high thermal gradient), a gap appears in the otherwise continuous range of stable array spacings. Close to this gap, a sustained oscillatory regime appears with a period that compares quantitatively well with experiment. For control parameters where this gap exist, oscillations typically occur for spacings at the edge of the gap. However, after a change of growth conditions, oscillations can also occur for nearby values of control parameters where this gap just closes and a continuous range of spacings exists. In addition, sustained oscillations at to the opening of this stable gap exhibit a slow periodic modulation of the phase-shift among cells with a slower period of several hours. While long-range coherence of breathing modes can be achieved in simulations for a perfect spatial arrangement of cells as initial condition, global disorder is observed in both three-dimensional experiments and simulations from realistic noisy initial conditions. The, erratic tip splitting events promoted by large amplitude oscillations contribute to maintaining the long-range array disorder, unlike in thin sample experiments where long-range coherence of oscillations is experimentally observable.« less

Dynamically Reconfigurable Metadevice Employing Nanostructured Phase-Change Materials

DOE PAGES

Zhu, Zhihua; Evans, Philip G.; Haglund, Richard F.; ...

2017-07-21

Mastering dynamic free-space spectral control and modulation in the near-infrared (NIR) and optical regimes remains a challenging task that is hindered by the available functional materials at high frequencies. In this work, we have realized an efficient metadevice capable of spectral control by minimizing the thermal mass of a vanadium dioxide phase-change material (PCM) and placing the PCM at the feed gap of a bow-tie field antenna. The device has an experimentally measured tuning range of up to 360 nm in the NIR and a modulation depth of 33% at the resonant wavelength. The metadevice is configured for integrated andmore » local heating, leading to faster switching and more precise spatial control compared with devices based on phase-change thin films. We envisage that the combined advantages of this device will open new opportunities for signal processing, memory, security, and holography at optical frequencies.« less

Dynamically Reconfigurable Metadevice Employing Nanostructured Phase-Change Materials.

PubMed

Zhu, Zhihua; Evans, Philip G; Haglund, Richard F; Valentine, Jason G

2017-08-09

Mastering dynamic free-space spectral control and modulation in the near-infrared (NIR) and optical regimes remains a challenging task that is hindered by the available functional materials at high frequencies. In this work, we have realized an efficient metadevice capable of spectral control by minimizing the thermal mass of a vanadium dioxide phase-change material (PCM) and placing the PCM at the feed gap of a bow-tie field antenna. The device has an experimentally measured tuning range of up to 360 nm in the NIR and a modulation depth of 33% at the resonant wavelength. The metadevice is configured for integrated and local heating, leading to faster switching and more precise spatial control compared with devices based on phase-change thin films. We envisage that the combined advantages of this device will open new opportunities for signal processing, memory, security, and holography at optical frequencies.

A general formalism for phase space calculations

NASA Technical Reports Server (NTRS)

Norbury, John W.; Deutchman, Philip A.; Townsend, Lawrence W.; Cucinotta, Francis A.

1988-01-01

General formulas for calculating the interactions of galactic cosmic rays with target nuclei are presented. Methods for calculating the appropriate normalization volume elements and phase space factors are presented. Particular emphasis is placed on obtaining correct phase space factors for 2-, and 3-body final states. Calculations for both Lorentz-invariant and noninvariant phase space are presented.

Nonequilibrium life-cycles in Ocean Heat Content

NASA Astrophysics Data System (ADS)

Weiss, Jeffrey B.; Fox-Kemper, Baylor; Mandal, Dibyendu; Zia, Royce K. P.

2014-03-01

Natural climate variability can be considered as fluctuations in a nonequilibrium steady state. A fundamental property of nonequilibrium steady states is the phase space current which provides a preferred direction for fluctuations, and is manifested as preferred life-cycles for climate fluctuations. We propose a new quantity, the phase space angular momentum, to quantify the phase space rotation. In analogy with traditional angular momentum, which quantifies the rotation of mass in physical space, the phase space angular momentum quantifies the rotation of probability in phase space. It has the additional advantage that it is straightforward to calculate from a time series. We investigate the phase space angular momentum for fluctuations in ocean heat content in both observations and ocean general circulation models. We gratefully acknowledge financial support from the National Science Foundation (USA) under grant OCE 1245944.

Quantum mechanics on phase space: The hydrogen atom and its Wigner functions

NASA Astrophysics Data System (ADS)

Campos, P.; Martins, M. G. R.; Fernandes, M. C. B.; Vianna, J. D. M.

2018-03-01

Symplectic quantum mechanics (SQM) considers a non-commutative algebra of functions on a phase space Γ and an associated Hilbert space HΓ, to construct a unitary representation for the Galilei group. From this unitary representation the Schrödinger equation is rewritten in phase space variables and the Wigner function can be derived without the use of the Liouville-von Neumann equation. In this article the Coulomb potential in three dimensions (3D) is resolved completely by using the phase space Schrödinger equation. The Kustaanheimo-Stiefel(KS) transformation is applied and the Coulomb and harmonic oscillator potentials are connected. In this context we determine the energy levels, the amplitude of probability in phase space and correspondent Wigner quasi-distribution functions of the 3D-hydrogen atom described by Schrödinger equation in phase space.

Fractional order PIλ controller synthesis for steam turbine speed governing systems.

PubMed

Chen, Kai; Tang, Rongnian; Li, Chuang; Lu, Junguo

2018-06-01

The current state of the art of fractional order stability theory is hardly to build connection between the time domain analysis and frequency domain synthesis. The existing tuning methodologies for fractional order PI λ D μ are not always satisfy the given gain crossover frequency and phase margin simultaneously. To overcome the drawbacks in the existing synthesis of fractional order controller, the synthesis of optimal fractional order PI λ controller for higher-order process is proposed. According to the specified phase margin, the corresponding upper boundary of gain crossover frequency and stability surface in parameter space are obtained. Sweeping the order parameter over λ∈(0,2), the complete set of stabilizing controller which guarantees both pre-specifying phase frequency characteristic can be collected. Whereafter, the optimal fractional order PI λ controller is applied to the speed governing systems of steam turbine generation units. The numerical simulation and hardware-in-the-loop simulation demonstrate the effectiveness and satisfactory closed-loop performance of obtained fractional order PI λ controller. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

KSC-2014-3534

NASA Image and Video Library

2014-08-15

CAPE CANAVERAL, Fla. – Former astronaut Greg Johnson, executive director of the Center for the Advancement of Science in Space, talks to Florida middle school students and their teachers before the start of the Zero Robotics finals competition at NASA Kennedy Space Center's Space Station Processing Facility in Florida. Students designed software to control Synchronized Position Hold Engage and Reorient Experimental Satellites, or SPHERES, and competed with other teams locally. The Zero Robotics is a robotics programming competition where the robots are SPHERES. The competition starts online, where teams program the SPHERES to solve an annual challenge. After several phases of virtual competition in a simulation environment that mimics the real SPHERES, finalists are selected to compete in a live championship aboard the space station. Students compete to win a technically challenging game by programming their strategies into the SPHERES satellites. The programs are autonomous and the students cannot control the satellites during the test. Photo credit: NASA/Daniel Casper

KSC-2014-3539

NASA Image and Video Library

2014-08-15

CAPE CANAVERAL, Fla. – Former astronaut Greg Johnson, executive director of the Center for the Advancement of Science in Space, talks to Florida middle school students and their teachers before the start of the Zero Robotics finals competition at NASA Kennedy Space Center's Space Station Processing Facility in Florida. Students designed software to control Synchronized Position Hold Engage and Reorient Experimental Satellites, or SPHERES, and competed with other teams locally. The Zero Robotics is a robotics programming competition where the robots are SPHERES. The competition starts online, where teams program the SPHERES to solve an annual challenge. After several phases of virtual competition in a simulation environment that mimics the real SPHERES, finalists are selected to compete in a live championship aboard the space station. Students compete to win a technically challenging game by programming their strategies into the SPHERES satellites. The programs are autonomous and the students cannot control the satellites during the test. Photo credit: NASA/Daniel Casper

KSC-2014-3538

NASA Image and Video Library

2014-08-15

CAPE CANAVERAL, Fla. – Former astronaut Greg Johnson, executive director of the Center for the Advancement of Science in Space, talks to Florida middle school students and their teachers before the start of the Zero Robotics finals competition at NASA Kennedy Space Center's Space Station Processing Facility in Florida. Students designed software to control Synchronized Position Hold Engage and Reorient Experimental Satellites, or SPHERES, and competed with other teams locally. The Zero Robotics is a robotics programming competition where the robots are SPHERES. The competition starts online, where teams program the SPHERES to solve an annual challenge. After several phases of virtual competition in a simulation environment that mimics the real SPHERES, finalists are selected to compete in a live championship aboard the space station. Students compete to win a technically challenging game by programming their strategies into the SPHERES satellites. The programs are autonomous and the students cannot control the satellites during the test. Photo credit: NASA/Daniel Casper

KSC-2014-3541

NASA Image and Video Library

2014-08-15

CAPE CANAVERAL, Fla. – Florida middle school students and their teachers watch the Zero Robotics finals competition broadcast live via webex from the International Space Station. The Florida teams are at the Space Station Processing Facility at NASA's Kennedy Space Center in Florida. Students designed software to control Synchronized Position Hold Engage and Reorient Experimental Satellites, or SPHERES, and competed with other teams locally. The Zero Robotics is a robotics programming competition where the robots are SPHERES. The competition starts online, where teams program the SPHERES to solve an annual challenge. After several phases of virtual competition in a simulation environment that mimics the real SPHERES, finalists are selected to compete in a live championship aboard the space station. Students compete to win a technically challenging game by programming their strategies into the SPHERES satellites. The programs are autonomous and the students cannot control the satellites during the test. Photo credit: NASA/Daniel Casper

The Final Count Down: A Review of Three Decades of Flight Controller Training Methods for Space Shuttle Mission Operations

NASA Technical Reports Server (NTRS)

Dittemore, Gary D.; Bertels, Christie

2011-01-01

Operations of human spaceflight systems is extremely complex, therefore the training and certification of operations personnel is a critical piece of ensuring mission success. Mission Control Center (MCC-H), at the Lyndon B. Johnson Space Center, in Houston, Texas manages mission operations for the Space Shuttle Program, including the training and certification of the astronauts and flight control teams. As the space shuttle program ends in 2011, a review of how training for STS-1 was conducted compared to STS-134 will show multiple changes in training of shuttle flight controller over a thirty year period. This paper will additionally give an overview of a flight control team s makeup and responsibilities during a flight, and details on how those teams have been trained certified over the life span of the space shuttle. The training methods for developing flight controllers have evolved significantly over the last thirty years, while the core goals and competencies have remained the same. In addition, the facilities and tools used in the control center have evolved. These changes have been driven by many factors including lessons learned, technology, shuttle accidents, shifts in risk posture, and generational differences. A primary method used for training Space Shuttle flight control teams is by running mission simulations of the orbit, ascent, and entry phases, to truly "train like you fly." The reader will learn what it is like to perform a simulation as a shuttle flight controller. Finally, the paper will reflect on the lessons learned in training for the shuttle program, and how those could be applied to future human spaceflight endeavors.

International Space Station Environmental Control and Life Support Emergency Response Verification for Node 1

NASA Technical Reports Server (NTRS)

Williams, David E.

2008-01-01

The International Space Station (ISS) Node 1 Environmental Control and Life Support (ECLS) System is comprised of five subsystems: Atmosphere Control and Supply (ACS), Atmosphere Revitalization (AR), Fire Detection and Suppression (FDS), Temperature and Humidity Control (THC), and Water Recovery and Management (WRM). This paper provides a summary of the Node 1 Emergency Response capability, which includes nominal and off-nominal FDS operation, off nominal ACS operation, and off-nominal THC operation. These subsystems provide the capability to help aid the crew members during an emergency cabin depressurization, a toxic spill, or a fire. The paper will also provide a discussion of the detailed Node 1 ECLS Element Verification methodologies for operation of the Node 1 Emergency Response hardware operations utilized during the Qualification phase.

James Webb Space Telescope Optical Simulation Testbed: Segmented Mirror Phase Retrieval Testing

NASA Astrophysics Data System (ADS)

Laginja, Iva; Egron, Sylvain; Brady, Greg; Soummer, Remi; Lajoie, Charles-Philippe; Bonnefois, Aurélie; Long, Joseph; Michau, Vincent; Choquet, Elodie; Ferrari, Marc; Leboulleux, Lucie; Mazoyer, Johan; N’Diaye, Mamadou; Perrin, Marshall; Petrone, Peter; Pueyo, Laurent; Sivaramakrishnan, Anand

2018-01-01

The James Webb Space Telescope (JWST) Optical Simulation Testbed (JOST) is a hardware simulator designed to produce JWST-like images. A model of the JWST three mirror anastigmat is realized with three lenses in form of a Cooke Triplet, which provides JWST-like optical quality over a field equivalent to a NIRCam module, and an Iris AO segmented mirror with hexagonal elements is standing in for the JWST segmented primary. This setup successfully produces images extremely similar to NIRCam images from cryotesting in terms of the PSF morphology and sampling relative to the diffraction limit.The testbed is used for staff training of the wavefront sensing and control (WFS&C) team and for independent analysis of WFS&C scenarios of the JWST. Algorithms like geometric phase retrieval (GPR) that may be used in flight and potential upgrades to JWST WFS&C will be explored. We report on the current status of the testbed after alignment, implementation of the segmented mirror, and testing of phase retrieval techniques.This optical bench complements other work at the Makidon laboratory at the Space Telescope Science Institute, including the investigation of coronagraphy for segmented aperture telescopes. Beyond JWST we intend to use JOST for WFS&C studies for future large segmented space telescopes such as LUVOIR.

Inhibition in a microgravity environment of the recovery of Escherichia coli cells damaged by heavy ion beams during the NASDA ISS phase I program of NASA Shuttle/Mir mission no. 6.

PubMed

Harada, K; Sugahara, T; Ohnishi, T; Ozaki, Y; Obiya, Y; Miki, S; Miki, T; Imamura, M; Kobayashi, Y; Watanabe, H; Akashi, M; Furusawa, Y; Mizuma, N; Yamanaka, H; Ohashi, E; Yamaoka, C; Yajima, M; Fukui, M; Nakano, T; Takahashi, S; Amano, T; Sekikawa, K; Yanagawa, K; Nagaoka, S

1998-05-01

We participated in a space experiment, part of the National Space Development Agency of Japan (NASDA) Phase I Space Radiation Environment Measurement Program, conducted during the National Aeronautics and Space Administration (NASA) Shuttle/Mir Mission No. 6 (S/MM-6) project. The aim of our study was to investigate the effects of microgravity on the DNA repair processes of living organisms in the in orbit. Heavy ion beam radiation- or ç-irradiation-damaged biological samples of Escherichia coli and the radioresistant bacterium Deinococcus radiodurans were prepared and placed in a biospecimen box, which was loaded into the RRMD III sensor unit of the Space Shuttle. Two identical sets of samples were left in the Spacehab's Payload Processing Facility (SPPF) in Florida, USA, as a control. (flight No. STS-84) was launched from NASA John F. Kennedy Space Center (KSC) in Florida, USA, on May 15, 1997. The mission duration was 9.22 days. An astronaut activated the biological samples in the biospecimen box in the Spacehab during orbit in order to start repair of the DNA damaged by heavy ion beams or ç-irradiation and the samples were incubated for 19 h 35 min at about 22ûC, the cabin temperature. The control specimens in the SPPF were subjected to the same treatment under terrestrial gravity. After returned to earth, we investigated cell recovery by comparing the repair of the radiation-damaged DNA of E. coli and D. radiodurans in the microgravity environment in space with that on Earth. The results indicated that the DNA repair process of E. coli, but not of D. radiodurans, cells was inhibited in a microgravity environment.

Active debris removal GNC challenges over design and required ground validation

NASA Astrophysics Data System (ADS)

Colmenarejo, Pablo; Avilés, Marcos; di Sotto, Emanuele

2015-06-01

Because of the exponential growth of space debris, the access to space in the medium-term future is considered as being seriously compromised, particularly within LEO polar Sun-synchronous orbits and within geostationary orbits. The active debris removal (ADR) application poses new and challenging requirements on: first, the new required Guidance, Navigation and Control (GNC) technologies and, second, how to validate these new technologies before being applied in real missions. There is no doubt about the strong safety and collision risk aspects affecting the real operational ADR missions. But it shall be considered that even ADR demonstration missions will be affected by significant risk of collision during the demonstration, and that the ADR GNC systems/technologies to be used shall be well mature before using/demonstrating them in space. Specific and dedicated on-ground validation approaches, techniques and facilities are mandatory. The different ADR techniques can be roughly catalogued in three main groups (rigid capture, non-rigid capture and contactless). All of them have a strong impact on the GNC system of the active vehicle during the capture/proximity phase and, particularly, during the active vehicle/debris combo control phase after capture and during the de-orbiting phase. The main operational phases on an ADR scenario are: (1) ground controlled phase (ADR vehicle and debris are far), (2) fine orbit synchronization phase (ADR vehicle to reach debris ±V-bar), (3) short range phase (along track distance reduction till 10-100 s of metres), (4) terminal approach/capture phase and (5) de-orbiting. While phases 1-3 are somehow conventional and already addressed in detail during past/on-going studies related to rendezvous and/or formation flying, phases 4-5 are very specific and not mature in terms of GNC needed technologies and HW equipment. GMV is currently performing different internal activities and ESA studies/developments related to ADR mission, GNC and capture technologies. This paper focuses on some specific aspects and technologies related to ADR terminal phases involved technologies and ground validation approaches: (1) Terminal ADR approach phase using visual-based navigation (VBN). Potential Image Processing techniques and preliminary performances will be described, together with the challenge of generating on-ground realistic images as input for the HW/SW VBN system. Some results of image generation (including comparison with real flight image missions) and processing using GMV's Optical Laboratory (image generation by rendering spacecraft 3D models and projecting on a screen in front of the HW camera) and using GMV's platform-art ® laboratory to reproduce space-realistic physical scenarios (to be captured by a HW camera) using 1:1 physical spacecraft mock-ups in an absolutely dark environment with a Sun-like single illumination source. (2) Ground validation of GNC systems based on HW-in-the-Loop (HIL) test facilities, including realistic space-representative avionics (at processor, interfaces and real-time operating system), realistic and air-to-air stimulated breadboard perception sensors (IMU, optical cameras, laser 3D sensors) through the use of dynamic robotic devices hosting the active vehicle and debris mock-ups and reproducing accurately the spatial relative dynamic corresponding to an ADR scenario. This type of ground validation can effectively achieve validation in relevant environment, till TRL (Technology Readiness Level) 5/6 on ground and minimizing the uncertainty/risk of such technologies/systems with respect to its operational use. Description and video demonstration of some ADR applicable test case/s using GMV's platform-art ® dynamic test facility will be included. Particular attention will be paid on the needed type of structural/functional active ADR vehicle and debris mock-ups, force/torque measurement and feedback capability over debris contact or momentum exchange actions, ground gravity compensation.

A Two-Phase Space Resection Model for Accurate Topographic Reconstruction from Lunar Imagery with PushbroomScanners

PubMed Central

Xu, Xuemiao; Zhang, Huaidong; Han, Guoqiang; Kwan, Kin Chung; Pang, Wai-Man; Fang, Jiaming; Zhao, Gansen

2016-01-01

Exterior orientation parameters’ (EOP) estimation using space resection plays an important role in topographic reconstruction for push broom scanners. However, existing models of space resection are highly sensitive to errors in data. Unfortunately, for lunar imagery, the altitude data at the ground control points (GCPs) for space resection are error-prone. Thus, existing models fail to produce reliable EOPs. Motivated by a finding that for push broom scanners, angular rotations of EOPs can be estimated independent of the altitude data and only involving the geographic data at the GCPs, which are already provided, hence, we divide the modeling of space resection into two phases. Firstly, we estimate the angular rotations based on the reliable geographic data using our proposed mathematical model. Then, with the accurate angular rotations, the collinear equations for space resection are simplified into a linear problem, and the global optimal solution for the spatial position of EOPs can always be achieved. Moreover, a certainty term is integrated to penalize the unreliable altitude data for increasing the error tolerance. Experimental results evidence that our model can obtain more accurate EOPs and topographic maps not only for the simulated data, but also for the real data from Chang’E-1, compared to the existing space resection model. PMID:27077855

A Two-Phase Space Resection Model for Accurate Topographic Reconstruction from Lunar Imagery with PushbroomScanners.

PubMed

Xu, Xuemiao; Zhang, Huaidong; Han, Guoqiang; Kwan, Kin Chung; Pang, Wai-Man; Fang, Jiaming; Zhao, Gansen

2016-04-11

Exterior orientation parameters' (EOP) estimation using space resection plays an important role in topographic reconstruction for push broom scanners. However, existing models of space resection are highly sensitive to errors in data. Unfortunately, for lunar imagery, the altitude data at the ground control points (GCPs) for space resection are error-prone. Thus, existing models fail to produce reliable EOPs. Motivated by a finding that for push broom scanners, angular rotations of EOPs can be estimated independent of the altitude data and only involving the geographic data at the GCPs, which are already provided, hence, we divide the modeling of space resection into two phases. Firstly, we estimate the angular rotations based on the reliable geographic data using our proposed mathematical model. Then, with the accurate angular rotations, the collinear equations for space resection are simplified into a linear problem, and the global optimal solution for the spatial position of EOPs can always be achieved. Moreover, a certainty term is integrated to penalize the unreliable altitude data for increasing the error tolerance. Experimental results evidence that our model can obtain more accurate EOPs and topographic maps not only for the simulated data, but also for the real data from Chang'E-1, compared to the existing space resection model.

Neurovestibular Effects of Long-Duration Spaceflight: A Summary of Mir-Phase 1 Experiences

NASA Technical Reports Server (NTRS)

Richards, Jason T.; Clark, Jonathan B.; Oman, Charles M.; Marshburn, Thomas H.

2002-01-01

Space motion sickness and associated neurovestibular dysfunction though not completely understood - have been relatively well clinically and operationally characterized on short-duration (1-2 week) Space Shuttle missions (Oman, et al, 1984, 1986; Thornton, et al, 1987; Reschke, et al, 1994). Between March 1995 and June 1998, seven NASA astronauts flew on the Russian Mir space station, as "Phase 1" of the joint effort to build the International Space Station, and provided NASA with invaluable experience on the operational and biomedical problems associated with flights of up to six months in duration. The goal of this paper is to provide a summary of the available information on neurovestibular dysfunction, space motion sickness, and readaptation to Earth's gravity on the NASA Mir flights, based on a set of medical questionnaire data, transcripts, and interviews which are available from the NASA-Mir Phase I program. Records were incomplete and anecdotal. All references to specific crewmembers have been removed, to respect their individual privacy. Material was excerpted from multiple sources of information relating to neurologic function, sensory illusions and motion sickness of NASA-Mir Phase I Program crewmembers. Data were compiled by epoch (in-flight vs landing/postflight) and grouped by neurovestibular topic. The information was recorded either contemporaneously during or within days after landing, or retrospectively weeks to months later. Space motion sickness symptoms are more intense and longer in duration. Sense of spatial orientation takes at least a month to become "natural and instinctive" in space station structures, but mental survey knowledge is apparently not completely developed even after 3 months in some cases. Visual reorientation illusions (VRI) are more easily induced after long exposure to weightlessness. Head movements can cause illusory spinning sensations for up to 7 days postflight. Postural and balance control does not fully recover for at least a month postflight.

Technology achievements and projections for communication satellites of the future

NASA Technical Reports Server (NTRS)

Bagwell, J. W.

1986-01-01

Multibeam systems of the future using monolithic microwave integrated circuits to provide phase control and power gain are contrasted with discrete microwave power amplifiers from 10 to 75 W and their associated waveguide feeds, phase shifters and power splitters. Challenging new enabling technology areas include advanced electrooptical control and signal feeds. Large scale MMIC's will be used incorporating on chip control interfaces, latching, and phase and amplitude control with power levels of a few watts each. Beam forming algorithms for 80 to 90 deg. wide angle scanning and precise beam forming under wide ranging environments will be required. Satelllite systems using these dynamically reconfigured multibeam antenna systems will demand greater degrees of beam interconnectivity. Multiband and multiservice users will be interconnected through the same space platform. Monolithic switching arrays operating over a wide range of RF and IF frequencies are contrasted with current IF switch technology implemented discretely. Size, weight, and performance improvements by an order of magnitude are projected.

An investigation of quasi-inertial attitude control for a solar power satellite

NASA Technical Reports Server (NTRS)

Juang, J.-N.; Wang, S. J.

1982-01-01

An efficient means, a quasi-inertial attitude mode, is developed for maintaining the normal solar orientation of a space satellite for power collection in a synchronous orbit. Formulae are presented which establish the basic parametric properties for ideal quasi-inertial attitude and phasing. An active control system is necessary to compensate for the energy loss since energy dissipation in widely oscillating flexible bodies produces an instability of the quasi-inertial attitude in the sense that the spacecraft will tumble at the orbit rate. A fixed terminal time and state optimal control problem is formulated and an algorithm for determining the optimal control as a means for the periodical attitude and phase compensation is developed. The vehicle orientation affected by internal disturbance (structural flexibility) and external disturbances (e.g., drag forces) is maintained by a specialized controller design.

KSC-2014-3542

NASA Image and Video Library

2014-08-15

CAPE CANAVERAL, Fla. – Former astronaut Greg Johnson, at left, executive director of the Center for the Advancement of Science in Space, and NASA Kennedy Space Center Director Bob Cabana, visit with Florida middle school students and their teachers before the start of the Zero Robotics finals competition at NASA Kennedy Space Center's Space Station Processing Facility in Florida. Students designed software to control Synchronized Position Hold Engage and Reorient Experimental Satellites, or SPHERES, and competed with other teams locally. The Zero Robotics is a robotics programming competition where the robots are SPHERES. The competition starts online, where teams program the SPHERES to solve an annual challenge. After several phases of virtual competition in a simulation environment that mimics the real SPHERES, finalists are selected to compete in a live championship aboard the space station. Students compete to win a technically challenging game by programming their strategies into the SPHERES satellites. The programs are autonomous and the students cannot control the satellites during the test. Photo credit: NASA/Daniel Casper

Solving a Local Boundary Value Problem for a Nonlinear Nonstationary System in the Class of Feedback Controls

NASA Astrophysics Data System (ADS)

Kvitko, A. N.

2018-01-01

An algorithm convenient for numerical implementation is proposed for constructing differentiable control functions that transfer a wide class of nonlinear nonstationary systems of ordinary differential equations from an initial state to a given point of the phase space. Constructive sufficient conditions imposed on the right-hand side of the controlled system are obtained under which this transfer is possible. The control of a robotic manipulator is considered, and its numerical simulation is performed.

Environmental control and life support system analysis tools for the Space Station era

NASA Technical Reports Server (NTRS)

Blakely, R. L.; Rowell, L. F.

1984-01-01

This paper describes the concept of a developing emulation, simulation, sizing, and technology assessment program (ESSTAP) which can be used effectively for the various functional disciplines (structures, power, ECLSS, etc.) beginning with the initial system selection and conceptual design processes and continuing on through the mission operation and growth phases of the Space Station for the purpose of minimizing overall program costs. It will discuss the basic requirements for these tools, as currently envisioned for the Environmental Control and Life Support System (ECLSS), identifying their intended and potential uses and applications, and present examples and status of several representative tools. The development and applications of a Space Station Atmospheric Revitalization Subsystem (ARS) demonstration model to be used for concent verification will also be discussed.

Occluder closing behavior: a key factor in mechanical heart valve cavitation.

PubMed

Wu, Z J; Wang, Y; Hwang, N H

1994-04-01

A laser sweeping technique developed in this laboratory was found to be capable of monitoring the leaflet closing motion with microsecond precision. The leaflet closing velocity was measured inside the last three degrees before impact. Mechanical heart valve (MHV) leaflets were observed to close with a three-phase motion; the approaching phase, the decelerating phase, and the rebound phase, all of which take place within one to two milliseconds. The leaflet closing behavior depends mainly on the leaflet design and the hinge mechanism. Bileaflet and monoleaflet types of mechanical heart valves were tested in the mitral position in a physiologic mock circulatory flow loop, which incorporated a computer-controlled magnetic drive and an adjustable afterload system. The test loop was tuned to produce physiologic ventricular and aortic pressure wave forms at 70-120 beats/min, with the maximum ventricular dp/dt varying between 1500-5600 mmHg/sec. The experiments were conducted by controlling the cardiac output at a constant level between 2.0-9.0 liters/min. The measured time-displacement curve of each tested MHV leaflet and its geometry were taken as the input for computation of the squeeze flow field in the narrow gap space between the approaching leaflet and the valve housing. The results indicated rapid build-up of both the pressure and velocity in the gap field within microsecs before the impact. The pressure build-up in the gap space is apparently responsible for the leaflet deceleration before the impact. When the concurrent water hammer pressure reduction at closure was combined with the high energy squeeze jet ejected from the gap space, there were strong indications of the environment which favors micro cavitation inceptions in certain types of MHV.

A navigation and control system for an autonomous rescue vehicle in the space station environment

NASA Technical Reports Server (NTRS)

Merkel, Lawrence

1991-01-01

A navigation and control system was designed and implemented for an orbital autonomous rescue vehicle envisioned to retrieve astronauts or equipment in the case that they become disengaged from the space station. The rescue vehicle, termed the Extra-Vehicular Activity Retriever (EVAR), has an on-board inertial measurement unit ahd GPS receivers for self state estimation, a laser range imager (LRI) and cameras for object state estimation, and a data link for reception of space station state information. The states of the retriever and objects (obstacles and the target object) are estimated by inertial state propagation which is corrected via measurements from the GPS, the LRI system, or the camera system. Kalman filters are utilized to perform sensor fusion and estimate the state propagation errors. Control actuation is performed by a Manned Maneuvering Unit (MMU). Phase plane control techniques are used to control the rotational and translational state of the retriever. The translational controller provides station-keeping or motion along either Clohessy-Wiltshire trajectories or straight line trajectories in the LVLH frame of any sufficiently observed object or of the space station. The software was used to successfully control a prototype EVAR on an air bearing floor facility, and a simulated EVAR operating in a simulated orbital environment. The design of the navigation system and the control system are presented. Also discussed are the hardware systems and the overall software architecture.

On the origin of the phase-space diffusion limit in (dis)ordered protein aggregation

NASA Astrophysics Data System (ADS)

Gadomski, A.; Siódmiak, J.; Santamaría-Holek, I.

2013-08-01

Derivation of a phase-space diffusion limit (D-L) allows to obtain a useful formula for a characteristic width of the macroion-channeling filter, controlling model (dis)ordered protein aggregations in a non-ideal aqueous solution. The channel’s width is estimated at the order of an inner half-width of the Stern-type double layer circumventing the growing object and depends in turn on an interplay of the local thermal and electrostatic conditions. The interfacial channeling effect manifests at the edge of biomolecular hydration-duration dependent (non)Markovianity of the system. The interface vs. solution aggregation late-time dynamics are discussed in such local (non)isothermal context with the aim to suggest their experimental assessment.

Two-phase/two-phase heat exchanger simulation analysis

NASA Technical Reports Server (NTRS)

Kim, Rhyn H.

1992-01-01

The capillary pumped loop (CPL) system is one of the most desirable devices to dissipate heat energy in the radiation environment of the Space Station providing a relatively easy control of the temperature. A condenser, a component of the CPL system, is linked with a buffer evaporator in the form of an annulus section of a double tube heat exchanger arrangement: the concentric core of the double tube is the condenser; the annulus section is used as a buffer between the conditioned space and the radiation surrounding but works as an evaporator. A CPL system with this type of condenser is modeled to simulate its function numerically. Preliminary results for temperature variations of the system are shown and more investigations are suggested for further improvement.

Solid polymer electrolyte water electrolysis system development. [to generate oxygen for manned space station applications

NASA Technical Reports Server (NTRS)

1975-01-01

Solid polymer electrolyte technology used in a water electrolysis system (WES) to generate oxygen and hydrogen for manned space station applications was investigated. A four-man rated, low pressure breadboard water electrolysis system with the necessary instrumentation and controls was fabricated and tested. A six man rated, high pressure, high temperature, advanced preprototype WES was developed. This configuration included the design and development of an advanced water electrolysis module, capable of operation at 400 psig and 200 F, and a dynamic phase separator/pump in place of a passive phase separator design. Evaluation of this system demonstrated the goal of safe, unattended automated operation at high pressure and high temperature with an accumulated gas generation time of over 1000 hours.

Study of two-phase flows in reduced gravity

NASA Astrophysics Data System (ADS)

Roy, Tirthankar

Study of gas-liquid two-phase flows under reduced gravity conditions is extremely important. One of the major applications of gas-liquid two-phase flows under reduced gravity conditions is in the design of active thermal control systems for future space applications. Previous space crafts were characterized by low heat generation within the spacecraft which needed to be redistributed within the craft or rejected to space. This task could easily have been accomplished by pumped single-phase loops or passive systems such as heat pipes and so on. However with increase in heat generation within the space craft as predicted for future missions, pumped boiling two-phase flows are being considered. This is because of higher heat transfer co-efficients associated with boiling heat transfer among other advantages. Two-phase flows under reduced gravity conditions also find important applications in space propulsion as in space nuclear power reactors as well as in many other life support systems of space crafts. Two-fluid model along with Interfacial Area Transport Equation (IATE) is a useful tool available to predict the behavior of gas-liquid two-phase flows under reduced gravity conditions. It should be noted that considerable differences exist between two-phase flows under reduced and normal gravity conditions especially for low inertia flows. This is because due to suppression of the gravity field the gas-liquid two-phase flows take a considerable time to develop under reduced gravity conditions as compared to normal gravity conditions. Hence other common methods of analysis applicable for fully developed gas-liquid two-phase flows under normal gravity conditions, like flow regimes and flow regime transition criteria, will not be applicable to gas-liquid two-phase flows under reduced gravity conditions. However the two-fluid model and the IATE need to be evaluated first against detailed experimental data obtained under reduced gravity conditions. Although lot of studies have been done in the past to understand the global structure of gas-liquid two-phase flows under reduced gravity conditions, using experimental setups aboard drop towers or aircrafts flying parabolic flights, detailed data on local structure of such two-phase flows are extremely rare. Hence experiments were carried out in a 304 mm inner diameter (ID) test facility on earth. Keeping in mind the detailed experimental data base that needs to be generated to evaluate two-fluid model along with IATE, ground based simulations provide the only economic path. Here the reduced gravity condition is simulated using two-liquids of similar densities (water and Therminol 59 RTM in the present case). Only adiabatic two-phase flows were concentrated on at this initial stage. Such a large diameter test section was chosen to study the development of drops to their full extent (it is to be noted that under reduced gravity conditions the stable bubble size in gas-liquid two-phase flows is much larger than that at normal gravity conditions). Twelve flow conditions were chosen around predicted bubbly flow to cap-bubbly flow transition region. Detailed local data was obtained at ten radial locations for each of three axial locations using state-of-the art multi-sensor conductivity probes. The results are presented and discussed. Also one-group as well as two-group, steady state, one-dimensional IATE was evaluated against data obtained here and by other researchers, and the results presented and discussed.

Investigation of phase-change coatings for variable thermal control of spacecraft

NASA Technical Reports Server (NTRS)

Kelliher, W. C.; Young, P. R.

1972-01-01

An investigation was conducted to determine the feasibility of producing a spacecraft coating system that could vary the ratio of its solar absorptance to thermal emittance to adjust automatically for changes in the thermal balance of a spacecraft. This study resulted in a new concept called the phase-change effect which uses the change that occurs in the optical properties of many materials during the phase transition from a crystalline solid to an amorphous material. A series of two-component model coatings was developed which, when placed on a highly reflecting substrate, exhibited a sharp decrease in solar absorptance within a narrow temperature range. A variable thermal control coating can have a significant amount of temperature regulation with the phase-change effect. Data are presented on several crystallite-polymer formulations, their physical and optical properties, and associated phase-change temperatures. Aspects pertaining to their use in a space environment and an example of the degree of thermal regulation attainable with these coatings is also given.

The Potential of Phased Arrays for Planetary Exploration

NASA Astrophysics Data System (ADS)

Pogorzelski, Ronald J.

2000-01-01

Phased array antennas provide a set of operational capabilities which are very attractive for certain mission applications and not very attractive for others. Such antennas are by no means a panacea for telecommunications. In this paper the features of phased arrays are reviewed and their implications for space missions are considered in terms of benefits and costs. The primary capability provided by a phased array is electronic beam agility. The beam direction may be controlled at electronic speeds (vs. mechanical actuation) permitting time division multiplexing of multiple "users." Moreover, the beam direction can be varied over a full hemisphere (for a planar array). On the other hand, such antennas are typically much more complicated than the more commonly used reflectors and horns and this implies higher cost. In some applications, this increased cost must be accepted if the mission is to be carried out at all. The SIR-C radar is an example of such a case albeit not for deep space. Assuming for the sake of argument that the complexity and cost of a phased array can be significantly reduced, where can such antennas be of value in the future of planetary exploration? Potential applications to be discussed are planetary rovers, landers, and orbiters including both the areosynchronous and low orbit varieties. In addition, consideration is given to links from deep space to earth. As may be fairly obvious, the deep space link to earth would not benefit from the wide angle steering capability provided by a phase array whereas a rover could gain advantage from the capability to steer a beam anywhere in the sky. In the rover case, however, physical size of the aperture becomes a significant factor which, of course, has implications regarding the choice of frequency band. Recent research work concerning phased arrays has suggested that future phased arrays might be made less complex and, therefore, less costly. Successful realization of such phased arrays would enable many of the planetary missions discussed in this paper and significantly broaden the telecommunications capabilities available to the mission designers of the future.

Functional brain networks in Alzheimer's disease: EEG analysis based on limited penetrable visibility graph and phase space method

NASA Astrophysics Data System (ADS)

Wang, Jiang; Yang, Chen; Wang, Ruofan; Yu, Haitao; Cao, Yibin; Liu, Jing

2016-10-01

In this paper, EEG series are applied to construct functional connections with the correlation between different regions in order to investigate the nonlinear characteristic and the cognitive function of the brain with Alzheimer's disease (AD). First, limited penetrable visibility graph (LPVG) and phase space method map single EEG series into networks, and investigate the underlying chaotic system dynamics of AD brain. Topological properties of the networks are extracted, such as average path length and clustering coefficient. It is found that the network topology of AD in several local brain regions are different from that of the control group with no statistically significant difference existing all over the brain. Furthermore, in order to detect the abnormality of AD brain as a whole, functional connections among different brain regions are reconstructed based on similarity of clustering coefficient sequence (CCSS) of EEG series in the four frequency bands (delta, theta, alpha, and beta), which exhibit obvious small-world properties. Graph analysis demonstrates that for both methodologies, the functional connections between regions of AD brain decrease, particularly in the alpha frequency band. AD causes the graph index complexity of the functional network decreased, the small-world properties weakened, and the vulnerability increased. The obtained results show that the brain functional network constructed by LPVG and phase space method might be more effective to distinguish AD from the normal control than the analysis of single series, which is helpful for revealing the underlying pathological mechanism of the disease.

Towards Supervising Remote Dexterous Robots Across Time Delay

NASA Technical Reports Server (NTRS)

Hambuchen, Kimberly; Bluethmann, William; Goza, Michael; Ambrose, Robert; Wheeler, Kevin; Rabe, Ken

2006-01-01

The President s Vision for Space Exploration, laid out in 2004, relies heavily upon robotic exploration of the lunar surface in early phases of the program. Prior to the arrival of astronauts on the lunar surface, these robots will be required to be controlled across space and time, posing a considerable challenge for traditional telepresence techniques. Because time delays will be measured in seconds, not minutes as is the case for Mars Exploration, uploading the plan for a day seems excessive. An approach for controlling dexterous robots under intermediate time delay is presented, in which software running within a ground control cockpit predicts the intention of an immersed robot supervisor, then the remote robot autonomously executes the supervisor s intended tasks. Initial results are presented.

KSC-2014-1419

NASA Image and Video Library

2014-01-06

HOUSTON – Chris Ferguson, a former space shuttle commander who is now director of Crew and Mission Operations for Boeing Space Exploration, takes the controls inside the company's CST-100 spacecraft simulator. To Ferguson's right, an engineer observes the exercise. Boeing demonstrated that the CST-100's software allows a human pilot to take over control of the spacecraft from the computer during all phases of a mission following separation from the launch vehicle. The pilot-in-the-loop demonstration at the Houston Product Support Center is a milestone under Boeing's Commercial Crew Integrated Capability agreement with the agency and its Commercial Crew Program. Photo credit: NASA/Bill Stafford

Verification of an analytic modeler for capillary pump loop thermal control systems

NASA Technical Reports Server (NTRS)

Schweickart, R. B.; Neiswanger, L.; Ku, J.

1987-01-01

A number of computer programs have been written to model two-phase heat transfer systems for space use. These programs support the design of thermal control systems and provide a method of predicting their performance in the wide range of thermal environments of space. Predicting the performance of one such system known as the capillary pump loop (CPL) is the intent of the CPL Modeler. By modeling two developed CPL systems and comparing the results with actual test data, the CPL Modeler has proven useful in simulating CPL operation. Results of the modeling effort are discussed, together with plans for refinements to the modeler.

A flexible telerobotic system for space operations

NASA Technical Reports Server (NTRS)

Sliwa, N. O.; Will, R. W.

1987-01-01

The objective and design of a proposed goal-oriented knowledge-based telerobotic system for space operations is described. This design effort encompasses the elements of the system executive and user interface and the distribution and general structure of the knowledge base, the displays, and the task sequencing. The objective of the design effort is to provide an expandable structure for a telerobotic system that provides cooperative interaction between the human operator and computer control. The initial phase of the implementation provides a rule-based, goal-oriented script generator to interface to the existing control modes of a telerobotic research system, in the Intelligent Systems Research Lab at NASA Research Center.

New Marshall Center Test Stand 4697 Construction Time-Lapse

NASA Image and Video Library

2016-09-27

In less than two minutes watch structural Test Stand 4697 rise at NASA's Marshall Space Flight Center from the start of construction in May 2014 to the end of the stand's construction phase in September 2016. The stand will subject the 196,000-gallon liquid oxygen tank of the Space Launch System's massive core stage to the same stresses and pressures it must endure at launch and in flight. Now, Marshall teams are installing sophisticated fluid transfer and pressurization systems, hydraulic controls, electrical control and data systems, fiber optics cables and special test equipment to prepare for the arrival of the test tank in 2017. (NASA/MSFC/David Olive)

Structural active cooling applications for the Space Shuttle.

NASA Technical Reports Server (NTRS)

Masek, R. V.; Niblock, G. A.; Huneidi, F.

1972-01-01

Analytic and experimental studies have been conducted to evaluate a number of active cooling approaches to structural thermal protection for the Space Shuttle. The primary emphasis was directed toward the thermal protection system. Trade study results are presented for various heat shield material and TPS arrangements. Both metallic and reusable surface insulation (RSI) concepts were considered. Active systems heat sinks consisted of hydrogen, phase change materials, and expendable water. If consideration is given only to controlling the surface temperature, passive TPS was found to provide the most efficient system. Use of active cooling which incorporates some interior temperature control made the thermally less efficient RSI system more attractive.

Natural convection in low-g environments

NASA Technical Reports Server (NTRS)

Grodzka, P. G.; Bannister, T. C.

1974-01-01

The present state of knowledge in the area of low-g natural convection is reviewed, taking into account a number of experiments conducted during the Apollo 14, 16, and 17 space flights. Convections due to steady low-g accelerations are considered. Steady g-levels result from spacecraft rotation, gravity gradients, solar wind, and solar pressure. Varying g-levels are produced by engine burns, attitude control maneuvers, and onboard vibrations from machinery or astronaut movement. Thermoacoustic convection in a low-g environment is discussed together with g-jitter convection, surface tension-driven convection, electrohydrodynamics under low-g conditions, phase change convection, and approaches for the control and the utilization of convection in space.

Crystal growth of GaAs in space

NASA Technical Reports Server (NTRS)

Gatos, H. C.; Lagowski, J.; Pawlowicz, L. M.; Dabkowski, F.; Li, C. J.

1984-01-01

It is shown that stoichiometry variations in the GaAs melt during growth constitute the most critical parameter regarding defect formations and their interactions; this defect structure determines all relevant characteristics of GaAs. Convection in the melt leads to stoichiometric variations. Growth in axial magnetic fields reduces convection and permits the study of defect structure. In order to control stoichiometry in space and to accommodate expansion during solidification, a partially confined configuration was developed. A triangular prism is employed to contain the growth melt. This configuration permits the presence of the desired vapor phase in contact with the melt for controlling the melt stoichiometry.

International Space Station Environmental Control and Life Support System Status: 2010 - 2011

NASA Technical Reports Server (NTRS)

Williams, David E.; Gentry, Gregory J.

2010-01-01

The International Space Station (ISS) Environmental Control and Life Support (ECLS) system includes regenerative and non-regenerative technologies that provide the basic life support functions to support the crew, while maintaining a safe and habitable shirtsleeve environment. This paper provides a summary of the U.S. ECLS system activities over the past year, covering the period of time between March 2010 and February 2011 and the continued permanent presence of six crew members on ISS. Work continues on the last of the Phase 3 pressurized elements, commercial cargo resupply vehicles, and extension of the ISS service life from 2015 to 2020 or beyond.

Albumin transcytosis from the pleural space.

PubMed

Agostoni, Emilio; Bodega, Francesca; Zocchi, Luciano

2002-11-01

Occurrence of transcytosis in pleural mesothelium was verified by measuring removal of labeled macromolecules from pleural liquid in experiments without and with nocodazole. To this end, we injected 0.3 ml of Ringer-albumin with 750 microg of albumin-Texas red or with 600 microg of dextran 70-Texas red in the right pleural space of anesthetized rabbits, and after 3 h we measured pleural liquid volume, labeled macromolecule concentration, and, hence, labeled macromolecule quantity in the liquid of this space. Labeled albumin left was 318 +/- 28 microg in control and 419 +/- 17 microg in nocodazole experiments (means +/- SE); hence, whereas ventilation was similar its removal was greater (P < 0.01) in control experiments. Labeled dextran left was 283 +/- 10 microg in control and 381 +/- 21 microg in nocodazole experiments; hence, whereas ventilation was similar its removal was greater (P < 0.01) in control experiments. These findings indicate occurrence of transcytosis from the pleural space. Liquid removed by transcytosis was 0.05 ml/h. This amount times unlabeled albumin concentration under physiological conditions (10 mg/ml) times lumen-vesicle partition coefficient for albumin (0.78) provides fluid-phase albumin transcytosis: approximately 203 microg. h(-1) kg(-2/3). Transcytosis might contribute a relevant part of protein and liquid removal from the pleural space.

Identification and control of structures in space

NASA Technical Reports Server (NTRS)

Meirovitch, Leonard

1994-01-01

During the last phase of the project, emphasis has changed to flexible space robotics, by mutual agreement between Dr. R. C. Montgomery, NASA Technical Officer, and the Principal Investigator. Significant advances have been achieved over the period covered by this report. Research has been concerned with two main subjects: (1) the maneuvering and control of freely floating flexible space robots, and (2) the development of a theory for the motion of flexible multibody systems. Work on the first subject has resulted in two papers, both of them concerned with planar maneuvers. The first is concerned with the maneuvering and delivery of a payload to a certain point and in a certain orientation in space. The second is concerned with the docking maneuver with a target whose motion is not known a priori. Both papers will appear in the 'Journal of Guidance, Control, and Dynamics.' The second subject is concerned with the development of hybrid (ordinary and partial) differential equations for the three dimensional motion of flexible multibody systems, a subject of vital interest in flexible space robotics. The paper will appear in the 'Journal of Guidance, Control and Dynamics' in an issue dedicated to the memory of Lawrence W. Taylor, Jr. Abstracts and copies of the papers are hereby included.

Piezoelectric devices for vibration suppression: Modeling and application to a truss structure

NASA Technical Reports Server (NTRS)

Won, Chin C.; Sparks, Dean W., Jr.; Belvin, W. Keith; Sulla, Jeff L.

1993-01-01

For a space structure assembled from truss members, an effective way to control the structure may be to replace the regular truss elements by active members. The active members play the role of load carrying elements as well as actuators. A piezo strut, made of a stack of piezoceramics, may be an ideal active member to be integrated into a truss space structure. An electrically driven piezo strut generates a pair of forces, and is considered as a two-point actuator in contrast to a one-point actuator such as a thruster or a shaker. To achieve good structural vibration control, sensing signals compatible to the control actuators are desirable. A strain gage or a piezo film with proper signal conditioning to measure member strain or strain rate, respectively, are ideal control sensors for use with a piezo actuator. The Phase 0 CSI Evolutionary Model (CEM) at NASA Langley Research Center used cold air thrusters as actuators to control both rigid body motions and flexible body vibrations. For the Phase 1 and 2 CEM, it is proposed to use piezo struts to control the flexible modes and thrusters to control the rigid body modes. A tenbay truss structure with active piezo struts is built to study the modeling, controller designs, and experimental issues. In this paper, the tenbay structure with piezo active members is modelled using an energy method approach. Decentralized and centralized control schemes are designed and implemented, and preliminary analytical and experimental results are presented.

Information Dominance: Why the Army is Interested in Space Control

DTIC Science & Technology

2002-01-01

2002 2. REPORT TYPE 3. DATES COVERED 00-00-2002 to 00-00-2002 4. TITLE AND SUBTITLE Information Dominance : Why the Army is Interested in Space... dominance is a great consideration during all phases of the conflict. It is worth noting that information dominance in itself is not the end-all...goal but rather a key contributor in establishing decision superiority at all points in the conflict time line. The Information Dominance : Why the

Structural optimization of structured carbon-based energy-storing composite materials used in space vehicles.

PubMed

Yu, Jia; Yu, Zhichao; Tang, Chenlong

2016-07-04

The hot work environment of electronic components in the instrument cabin of spacecraft was researched, and a new thermal protection structure, namely graphite carbon foam, which is an impregnated phase-transition material, was adopted to implement the thermal control on the electronic components. We used the optimized parameters obtained from ANSYS to conduct 2D optimization, 3-D modeling and simulation, as well as the strength check. Finally, the optimization results were verified by experiments. The results showed that after optimization, the structured carbon-based energy-storing composite material could reduce the mass and realize the thermal control over electronic components. This phase-transition composite material still possesses excellent temperature control performance after its repeated melting and solidifying.

Dissolution kinetics of iron-, manganese-, and copper-containing synthetic hydroxyapatites

NASA Technical Reports Server (NTRS)

Sutter, B.; Hossner, L. R.; Ming, D. W.

2005-01-01

Micronutrient-substituted synthetic hydroxyapatite (SHA) is being evaluated by the National Aeronautics and Space Administration's (NASA) Advanced Life Support (ALS) Program for crop production on long-duration human missions to the International Space Station or for future Lunar or Martian outposts. The stirred-flow technique was utilized to characterize Ca, P, Fe, Mn, and Cu release characteristics from Fe-, Mn-, and Cu-containing SHA in deionized (DI) water, citric acid, and diethylene-triamine-pentaacetic acid (DTPA). Initially, Ca and P release rates decreased rapidly with time and were controlled by a non-SHA calcium phosphate phase(s) with low Ca/P solution molar ratios (0.91-1.51) relative to solid SHA ratios (1.56-1.64). At later times, Ca/P solution molar ratios (1.47-1.79) were near solid SHA ratios and release rates decreased slowly indicating that SHA controlled Ca and P release. Substituted SHA materials had faster dissolution rates relative to unsubstituted SHA. The initial metal release rate order was Mn >> Cu > Fe which followed metal-oxide/phosphate solubility suggesting that poorly crystalline metal-oxides/phosphates were dominating metal release. Similar metal release rates for all substituted SHA (approximately 0.01 cmol kg-1 min-1) at the end of the DTPA experiment indicated that SHA dissolution was supplying the metals into solution and that poorly crystalline metal-oxide/phosphates were not controlling metal release. Results indicate that non-SHA Ca-phosphate phases and poorly crystalline metal-oxide/phosphates will contribute Ca, P, and metals. After these phases have dissolved, substituted SHA will be the source of Ca, P, and metals for plants.

Intelligent Robotic Systems Study (IRSS), phase 3

NASA Technical Reports Server (NTRS)

1991-01-01

This phase of the Intelligent Robotic Systems Study (IRSS) examines some basic dynamics and control issues for a space manipulator attached to its worksite through a compliant base. One example of this scenario is depicted, which is a simplified, planar representation of the Flight Telerobotic Servicer (FTS) Development Test Flight 2 (DTF-2) experiment. The system consists of 4 major components: (1) dual FTS arms to perform dextrous tasks; (2) the main body to house power and electronics; (3) an Attachment Stabilization and Positioning Subsystem (ASPS) to provide coarse positioning and stabilization of the arms, and (4) the Worksite Attachment Mechanism (WAM) which anchors the system to its worksite, such as a Space Station truss node or Shuttle bay platform. The analysis is limited to the DTF-2 scenario. The goal is to understand the basic interaction dynamics between the arm, the positioner and/or stabilizer, and the worksite. The dynamics and controls simulation model are described. Analysis and simulation results are presented.

Launch vehicle design and GNC sizing with ASTOS

NASA Astrophysics Data System (ADS)

Cremaschi, Francesco; Winter, Sebastian; Rossi, Valerio; Wiegand, Andreas

2018-03-01

The European Space Agency (ESA) is currently involved in several activities related to launch vehicle designs (Future Launcher Preparatory Program, Ariane 6, VEGA evolutions, etc.). Within these activities, ESA has identified the importance of developing a simulation infrastructure capable of supporting the multi-disciplinary design and preliminary guidance navigation and control (GNC) design of different launch vehicle configurations. Astos Solutions has developed the multi-disciplinary optimization and launcher GNC simulation and sizing tool (LGSST) under ESA contract. The functionality is integrated in the Analysis, Simulation and Trajectory Optimization Software for space applications (ASTOS) and is intended to be used from the early design phases up to phase B1 activities. ASTOS shall enable the user to perform detailed vehicle design tasks and assessment of GNC systems, covering all aspects of rapid configuration and scenario management, sizing of stages, trajectory-dependent estimation of structural masses, rigid and flexible body dynamics, navigation, guidance and control, worst case analysis, launch safety analysis, performance analysis, and reporting.

Chaos as the hub of systems dynamics. The part I-The attitude control of spacecraft by involving in the heteroclinic chaos

NASA Astrophysics Data System (ADS)

Doroshin, Anton V.

2018-06-01

In this work the chaos in dynamical systems is considered as a positive aspect of dynamical behavior which can be applied to change systems dynamical parameters and, moreover, to change systems qualitative properties. From this point of view, the chaos can be characterized as a hub for the system dynamical regimes, because it allows to interconnect separated zones of the phase space of the system, and to fulfill the jump into the desirable phase space zone. The concretized aim of this part of the research is to focus on developing the attitude control method for magnetized gyrostat-satellites, which uses the passage through the intentionally generated heteroclinic chaos. The attitude dynamics of the satellite/spacecraft in this case represents the series of transitions from the initial dynamical regime into the chaotic heteroclinic regime with the subsequent exit to the final target dynamical regime with desirable parameters of the attitude dynamics.

TU-AB-BRC-07: Efficiency of An IAEA Phase-Space Source for a Low Energy X-Ray Tube Using Egs++

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watson, PGF; Renaud, MA; Seuntjens, J

Purpose: To extend the capability of the EGSnrc C++ class library (egs++) to write and read IAEA phase-space files as a particle source, and to assess the relative efficiency gain in dose calculation using an IAEA phase-space source for modelling a miniature low energy x-ray source. Methods: We created a new ausgab object to score particles exiting a user-defined geometry and write them to an IAEA phase-space file. A new particle source was created to read from IAEA phase-space data. With these tools, a phase-space file was generated for particles exiting a miniature 50 kVp x-ray tube (The INTRABEAM System,more » Carl Zeiss). The phase-space source was validated by comparing calculated PDDs with a full electron source simulation of the INTRABEAM. The dose calculation efficiency gain of the phase-space source was determined relative to the full simulation. The efficiency gain as a function of i) depth in water, and ii) job parallelization was investigated. Results: The phase-space and electron source PDDs were found to agree to 0.5% RMS, comparable to statistical uncertainties. The use of a phase-space source for the INTRABEAM led to a relative efficiency gain of greater than 20 over the full electron source simulation, with an increase of up to a factor of 196. The efficiency gain was found to decrease with depth in water, due to the influence of scattering. Job parallelization (across 2 to 256 cores) was not found to have any detrimental effect on efficiency gain. Conclusion: A set of tools has been developed for writing and reading IAEA phase-space files, which can be used with any egs++ user code. For simulation of a low energy x-ray tube, the use of a phase-space source was found to increase the relative dose calculation efficiency by factor of up to 196. The authors acknowledge partial support by the CREATE Medical Physics Research Training Network grant of the Natural Sciences and Engineering Research Council (Grant No. 432290).« less

Investigating multiphoton phenomena using nonlinear dynamics

NASA Astrophysics Data System (ADS)

Huang, Shu

Many seemingly simple systems can display extraordinarily complex dynamics which has been studied and uncovered through nonlinear dynamical theory. The leitmotif of this thesis is changing phase-space structures and their (linear or non-linear) stabilities by adding control functions (which act on the system as external perturbations) to the relevant Hamiltonians. These phase-space structures may be periodic orbits, invariant tori or their stable and unstable manifolds. One-electron systems and diatomic molecules are fundamental and important staging ground for new discoveries in nonlinear dynamics. In past years, increasing emphasis and effort has been put on the control or manipulation of these systems. Recent developments of nonlinear dynamical tools can provide efficient ways of doing so. In the first subtopic of the thesis, we are adding a control function to restore tori at prescribed locations in phase space. In the remainder of the thesis, a control function with parameters is used to change the linear stability of the periodic orbits which govern the processes in question. In this thesis, we report our theoretical analyses on multiphoton ionization of Rydberg atoms exposed to strong microwave fields and the dissociation of diatomic molecules exposed to bichromatic lasers using nonlinear dynamical tools. This thesis is composed of three subtopics. In the first subtopic, we employ local control theory to reduce the stochastic ionization of hydrogen atom in a strong microwave field by adding a relatively small control term to the original Hamiltonian. In the second subtopic, we perform periodic orbit analysis to investigate multiphoton ionization driven by a bichromatic microwave field. Our results show quantitative and qualitative agreement with previous studies, and hence identify the mechanism through which short periodic orbits organize the dynamics in multiphoton ionization. In addition, we achieve substantial time savings with this approach. In the third subtopic we extend our periodic orbit analysis to the dissociation of diatomic molecules driven by a bichromatic laser. In this problem, our results based on periodic orbit analysis again show good agreement with previous work, and hence promise more potential applications of this approach in molecular physics.

Two-stage optics - High-acuity performance from low-acuity optical systems

NASA Technical Reports Server (NTRS)

Meinel, Aden B.; Meinel, Marjorie P.

1992-01-01

The concept of two-stage optics, developed under a program to enhance the performance, lower the cost, and increase the reliability of the 20-m Large Deployable Telescope, is examined. The concept permits the large primary mirror to remain as deployed or as space-assembled, with phasing and subsequent control of the system done by a small fully assembled optical active element placed at an exit pupil. The technique is being applied to correction of the fabrication/testing error in the Hubble Space Telescope primary mirror. The advantages offered by this concept for very large space telescopes are discussed.

System-Level Integrated Circuit (SLIC) Technology Development for Phased Array Antenna Applications

NASA Technical Reports Server (NTRS)

Windyka, John A.; Zablocki, Ed G.

1997-01-01

This report documents the efforts and progress in developing a 'system-level' integrated circuit, or SLIC, for application in advanced phased array antenna systems. The SLIC combines radio-frequency (RF) microelectronics, digital and analog support circuitry, and photonic interfaces into a single micro-hybrid assembly. Together, these technologies provide not only the amplitude and phase control necessary for electronic beam steering in the phased array, but also add thermally-compensated automatic gain control, health and status feedback, bias regulation, and reduced interconnect complexity. All circuitry is integrated into a compact, multilayer structure configured for use as a two-by-four element phased array module, operating at 20 Gigahertz, using a Microwave High-Density Interconnect (MHDI) process. The resultant hardware is constructed without conventional wirebonds, maintains tight inter-element spacing, and leads toward low-cost mass production. The measured performances and development issues associated with both the two-by-four element module and the constituent elements are presented. Additionally, a section of the report describes alternative architectures and applications supported by the SLIC electronics. Test results show excellent yield and performance of RF circuitry and full automatic gain control for multiple, independent channels. Digital control function, while suffering from lower manufacturing yield, also proved successful.

Space station molecular sieve development

NASA Technical Reports Server (NTRS)

Chang, C.; Rousseau, J.

1986-01-01

An essential function of a space environmental control system is the removal of carbon dioxide (CO2) from the atmosphere to control the partial pressure of this gas at levels lower than 3 mm Hg. The use of regenerable solid adsorbents for this purpose was demonstrated effectively during the Skylab mission. Earlier sorbent systems used zeolite molecular sieves. The carbon molecular sieve is a hydrophobic adsorbent with excellent potential for space station application. Although carbon molecular sieves were synthesized and investigated, these sieves were designed to simulate the sieving properties of 5A zeolite and for O2/N2 separation. This program was designed to develop hydrophobic carbon molecular sieves for CO2 removal from a space station crew environment. It is a first phase effort involved in sorbent material development and in demonstrating the utility of such a material for CO2 removal on space stations. The sieve must incorporate the following requirements: it must be hydrophobic; it must have high dynamic capacity for carbon dioxide at the low partial pressure of the space station atmosphere; and it must be chemiclly stable and will not generate contaminants.

Self control of when and how much to test face-name pairs in a novel spaced retrieval paradigm: an examination of age-related differences.

PubMed

Maddox, Geoffrey B; Balota, David A

2012-09-01

Although the mnemonic benefit of spaced retrieval is well established, the way in which participants naturally space their own retrieval is relatively unexplored. To examine this question, a novel experimental paradigm was developed in which young and healthy older adults were given control over the frequency and timing of retrieval practice in the context of an ongoing reading task. Results showed that both age groups naturally expanded the intervals of their retrieval practice. When instructed, younger adults but not older adults were better able to employ equal spaced retrieval during retrieval practice. However, even under equal spaced retrieval instructions, young adults included an early retrieval attempt prior to equally spacing their retrieval. Although memory performance was equivalent, secondary task performance was reduced in the experimenter-instructed condition compared with the participant-selected condition. The results overall indicate that both younger and older participants naturally monitor their memory and efficiently use testing to titrate the number and timing of retrieval attempts used during the acquisition phase.

Development of a Ground Test and Analysis Protocol for NASA's NextSTEP Phase 2 Habitation Concepts

NASA Technical Reports Server (NTRS)

Gernhardt, Michael L.; Beaton, Kara H.; Chappell, Steven P.; Bekdash, Omar S.; Abercromby, Andrew F. J.

2018-01-01

The NASA Next Space Technologies for Exploration Partnerships (NextSTEP) program is a public-private partnership model that seeks commercial development of deep space exploration capabilities to support human spaceflight missions around and beyond cislunar space. NASA first issued the Phase 1 NextSTEP Broad Agency Announcement to U.S. industries in 2014, which called for innovative cislunar habitation concepts that leveraged commercialization plans for low-Earth orbit. These habitats will be part of the Deep Space Gateway (DSG), the cislunar space station planned by NASA for construction in the 2020s. In 2016, Phase 2 of the NextSTEP program selected five commercial partners to develop ground prototypes. A team of NASA research engineers and subject matter experts (SMEs) have been tasked with developing the ground-test protocol that will serve as the primary means by which these Phase 2 prototypes will be evaluated. Since 2008, this core test team has successfully conducted multiple spaceflight analog mission evaluations utilizing a consistent set of operational tools, methods, and metrics to enable the iterative development, testing, analysis, and validation of evolving exploration architectures, operations concepts, and vehicle designs. The purpose of implementing a similar evaluation process for the Phase 2 Habitation Concepts is to consistently evaluate different commercial partner ground prototypes to provide data-driven, actionable recommendations for Phase 3. This paper describes the process by which the ground test protocol was developed and the objectives, methods, and metrics by which the NextSTEP Phase 2 Habitation Concepts will be rigorously and systematically evaluated. The protocol has been developed using both a top-down and bottom-up approach. Top-down development began with the Human Exploration and Operations Mission Directorate (HEOMD) exploration objectives and ISS Exploration Capability Study Team (IECST) candidate flight objectives. Strategic questions and associated rationales, derived from these candidate architectural objectives, provide the framework by which the ground-test protocol will address the DSG stack elements and configurations, systems and subsystems, and habitation, science, and EVA functions. From these strategic questions, high-level functional requirements for the DSG were drafted and associated ground-test objectives and analysis protocols were established. Bottom-up development incorporated objectives from NASA SMEs in autonomy, avionics and software, communication, environmental control and life support systems, exercise, extravehicular activity, exploration medical operations, guidance navigation and control, human factors and behavioral performance, human factors and habitability, logistics, Mission Control Center operations, power, radiation, robotics, safety and mission assurance, science, simulation, structures, thermal, trash management, and vehicle health. Top-down and bottom-up objectives were integrated to form overall functional requirements - ground-test objectives and analysis mapping. From this mapping, ground-test objectives were organized into those that will be evaluated through inspection, demonstration, analysis, subsystem standalone testing, and human-in-the-loop (HITL) testing. For the HITL tests, mission-like timelines, procedures, and flight rules have been developed to directly meet ground test objectives and evaluate specific functional requirements. Data collected from these assessments will be analyzed to determine the acceptability of habitation element configurations and the combinations of capabilities that will result in the best habitation platform to be recommended by the test team for Phase 3.

Optimal space communications techniques. [using digital and phase locked systems for signal processing

NASA Technical Reports Server (NTRS)

Schilling, D. L.

1974-01-01

Digital multiplication of two waveforms using delta modulation (DM) is discussed. It is shown that while conventional multiplication of two N bit words requires N2 complexity, multiplication using DM requires complexity which increases linearly with N. Bounds on the signal-to-quantization noise ratio (SNR) resulting from this multiplication are determined and compared with the SNR obtained using standard multiplication techniques. The phase locked loop (PLL) system, consisting of a phase detector, voltage controlled oscillator, and a linear loop filter, is discussed in terms of its design and system advantages. Areas requiring further research are identified.

Sensitivity of a Wave Structure to Initial Conditions

NASA Technical Reports Server (NTRS)

Duval, Walter M. B.; Duval, Walter M. B. (Technical Monitor)

2000-01-01

Microgravity experiments aimed at quantifying effects of gentler via controlled sinusoidal forcing transmitted on the interface between two miscible liquids have shown the evolution of a quasi -stationary four-mode wave structure oriented vertically. The sensitivity of the wave structure to phase angle variation is investigated computationally. We show that a slight variation of the phase angle is sufficient to cause a bifurcation to a two-mode structure. The dependence of phase angle on wave structure is attributed to sensitivity on initial conditions due to the strong nonlinearity of the coupled field equations for the parametric space of interest.

Quasi-Phase-Matched Supercontinuum Generation in Photonic Waveguides

NASA Astrophysics Data System (ADS)

Hickstein, Daniel D.; Kerber, Grace C.; Carlson, David R.; Chang, Lin; Westly, Daron; Srinivasan, Kartik; Kowligy, Abijith; Bowers, John E.; Diddams, Scott A.; Papp, Scott B.

2018-02-01

Supercontinuum generation (SCG) in integrated photonic waveguides is a versatile source of broadband light, and the generated spectrum is largely determined by the phase-matching conditions. Here we show that quasi-phase-matching via periodic modulations of the waveguide structure provides a useful mechanism to control the evolution of ultrafast pulses during supercontinuum generation. We experimentally demonstrate a quasi-phase-matched supercontinuum to the TE20 and TE00 waveguide modes, which enhances the intensity of the SCG in specific spectral regions by as much as 20 dB. We utilize higher-order quasi-phase-matching (up to the 16th order) to enhance the intensity in numerous locations across the spectrum. Quasi-phase-matching adds a unique dimension to the design space for SCG waveguides, allowing the spectrum to be engineered for specific applications.

Process for Encapsulating Protein Crystals

NASA Technical Reports Server (NTRS)

Morrison, Dennis R.; Mosier, Benjamin

2003-01-01

A process for growing protein crystals encapsulated within membranes has been invented. This process begins with the encapsulation of a nearly saturated aqueous protein solution inside semipermeable membranes to form microcapsules. The encapsulation is effected by use of special formulations of a dissolved protein and a surfactant in an aqueous first liquid phase, which is placed into contact with a second, immiscible liquid phase that contains one or more polymers that are insoluble in the first phase. The second phase becomes formed into the semipermeable membranes that surround microglobules of the first phase, thereby forming the microcapsules. Once formed, the microcapsules are then dehydrated osmotically by exposure to a concentrated salt or polymer solution. The dehydration forms supersaturated solutions inside the microcapsules, thereby enabling nucleation and growth of protein crystals inside the microcapsules. By suitable formulation of the polymer or salt solution and of other physical and chemical parameters, one can control the rate of transport of water out of the microcapsules through the membranes and thereby create physicochemical conditions that favor the growth, within each microcapsule, of one or a few large crystals suitable for analysis by x-ray diffraction. The membrane polymer can be formulated to consist of low-molecular-weight molecules that do not interfere with the x-ray diffraction analysis of the encapsulated crystals. During dehydration, an electrostatic field can be applied to exert additional control over the rate of dehydration. This protein-crystal-encapsulation process is expected to constitute the basis of protein-growth experiments to be performed on the space shuttle and the International Space Station. As envisioned, the experiments would involve the exposure of immiscible liquids to each other in sequences of steps under microgravitational conditions. The experiments are expected to contribute to knowledge of the precise conditions under which protein crystals form. By enhancing the ability to grow crystals suitable for x-ray diffraction analysis, this knowledge can be expected to benefit not only the space program but also medicine and the pharmaceutical industry.

Challenges in Characterizing and Controlling Complex Cellular Systems

NASA Astrophysics Data System (ADS)

Wikswo, John

2011-03-01

Multicellular dynamic biological processes such as developmental differentiation, wound repair, disease, aging, and even homeostasis can be represented by trajectories through a phase space whose extent reflects the genetic, post-translational, and metabolic complexity of the process - easily extending to tens of thousands of dimensions. Intra- and inter-cellular sensing and regulatory systems and their nested, redundant, and non-linear feed-forward and feed-back controls create high-dimensioned attractors in this phase space. Metabolism provides free energy to drive non-equilibrium processes and dynamically reconfigure attractors. Studies of single molecules and cells provide only minimalist projections onto a small number of axes. It may be difficult to infer larger-scale emergent behavior from linearized experiments that perform only small amplitude perturbations on a limited number of the dimensions. Complete characterization may succeed for bounded component problems, such as an individual cell cycle or signaling cascade, but larger systems problems will require a coarse-grained approach. Hence a new experimental and analytical framework is needed. Possibly one could utilize high-amplitude, multi-variable driving of the system to infer coarse-grained, effective models, which in turn can be tested by their ability to control systems behavior. Navigation at will between attractors in a high-dimensioned dynamical system will provide not only detailed knowledge of the shape of attractor basins, but also measures of underlying stochastic events such as noise in gene expression or receptor binding and how both affect system stability and robustness. Needed for this are wide-bandwidth methods to sense and actuate large numbers of intracellular and extracellular variables and automatically and rapidly infer dynamic control models. The success of this approach may be determined by how broadly the sensors and actuators can span the full dimensionality of the phase space. Supported by the Defense Threat Reduction Agency HDTRA-09-1-0013, NIH National Institute on Drug Abuse RC2DA028981, the National Academies Keck Futures Initiative, and the Vanderbilt Institute for Integrative Biosystems Research and Education.

Operational Concept for Flight Crews to Participate in Merging and Spacing of Aircraft

NASA Technical Reports Server (NTRS)

Baxley, Brian T.; Barmore, Bryan E.; Abbott, Terence S.; Capron, William R.

2006-01-01

The predicted tripling of air traffic within the next 15 years is expected to cause significant aircraft delays and create a major financial burden for the airline industry unless the capacity of the National Airspace System can be increased. One approach to improve throughput and reduce delay is to develop new ground tools, airborne tools, and procedures to reduce the variance of aircraft delivery to the airport, thereby providing an increase in runway throughput capacity and a reduction in arrival aircraft delay. The first phase of the Merging and Spacing Concept employs a ground based tool used by Air Traffic Control that creates an arrival time to the runway threshold based on the aircraft s current position and speed, then makes minor adjustments to that schedule to accommodate runway throughput constraints such as weather and wake vortex separation criteria. The Merging and Spacing Concept also employs arrival routing that begins at an en route metering fix at altitude and continues to the runway threshold with defined lateral, vertical, and velocity criteria. This allows the desired spacing interval between aircraft at the runway to be translated back in time and space to the metering fix. The tool then calculates a specific speed for each aircraft to fly while enroute to the metering fix based on the adjusted land timing for that aircraft. This speed is data-linked to the crew who fly this speed, causing the aircraft to arrive at the metering fix with the assigned spacing interval behind the previous aircraft in the landing sequence. The second phase of the Merging and Spacing Concept increases the timing precision of the aircraft delivery to the runway threshold by having flight crews using an airborne system make minor speed changes during enroute, descent, and arrival phases of flight. These speed changes are based on broadcast aircraft state data to determine the difference between the actual and assigned time interval between the aircraft pair. The airborne software then calculates a speed adjustment to null that difference over the remaining flight trajectory. Follow-on phases still under development will expand the concept to all types of aircraft, arriving from any direction, merging at different fixes and altitudes, and to any airport. This paper describes the implementation phases of the Merging and Spacing Concept, and provides high-level results of research conducted to date.

Ground controlled robotic assembly operations for Space Station Freedom

NASA Technical Reports Server (NTRS)

Parrish, Joseph C.

1991-01-01

A number of dextrous robotic systems and associated positioning and transportation devices are available on Space Station Freedom (SSF) to perform assembly tasks that would otherwise need to be performed by extravehicular activity (EVA) crewmembers. The currently planned operating mode for these robotic systems during the assembly phase is teleoperation by intravehicular activity (IVA) crewmembers. While this operating mode is less hazardous and expensive than manned EVA operations, and has insignificant control loop time delays, the amount of IVA time available to support telerobotic operations is much less than the anticipated requirements. Some alternative is needed to allow the robotic systems to perform useful tasks without exhausting the available IVA resources; ground control is one such alternative. The issues associated with ground control of SSF robotic systems to alleviate onboard crew time availability constraints are investigated. Key technical issues include the effect of communication time delays, the need for safe, reliable execution of remote operations, and required modifications to the SSF ground and flight system architecture. Time delay compensation techniques such as predictive displays and world model-based force reflection are addressed and collision detection and avoidance strategies to ensure the safety of the on-orbit crew, Orbiter, and SSF are described. Although more time consuming and difficult than IVA controlled teleoperations or manned EVA, ground controlled telerobotic operations offer significant benefits during the SSF assembly phase, and should be considered in assembly planning activities.

Overload control of artificial gravity facility using spinning tether system for high eccentricity transfer orbits

NASA Astrophysics Data System (ADS)

Gou, Xing-wang; Li, Ai-jun; Tian, Hao-chang; Wang, Chang-qing; Lu, Hong-shi

2018-06-01

As the major part of space life supporting systems, artificial gravity requires further study before it becomes mature. Spinning tether system is a good alternative solution to provide artificial gravity for the whole spacecraft other than additional devices, and its longer tether length could significantly reduce spinning velocity and thus enhance comfortability. An approximated overload-based feedback method is proposed to provide estimated spinning velocity signals for controller, so that gravity level could be accurately controlled without complicated GPS modules. System behavior in high eccentricity transfer orbits is also studied to give a complete knowledge of the spinning stabilities. The application range of the proposed method is studied in various orbit cases and spinning velocities, indicating that it is accurate and reliable for most of the mission phases especially for the final constant gravity level phase. In order to provide stable gravity level for transfer orbit missions, a sliding mode controller based on estimated angular signals is designed for closed-loop control. Numerical results indicate that the combination of overload-based feedback and sliding mode controller could satisfy most of the long-term artificial gravity missions. It is capable of forming flexible gravity environment in relatively good accuracy even in the lowest possible orbital radiuses and high eccentricity orbits of crewed space missions. The proposed scheme provides an effective tether solution for the artificial gravity construction in interstellar travel.

Selection of a Data Acquisition and Controls System Communications and Software Architecture for Johnson Space Center's Space Environment Simulation Laboratory Thermal and Vacuum Test Facilities

NASA Technical Reports Server (NTRS)

Jordan, Eric A.

2004-01-01

Upgrade of data acquisition and controls systems software at Johnson Space Center's Space Environment Simulation Laboratory (SESL) involved the definition, evaluation and selection of a system communication architecture and software components. A brief discussion of the background of the SESL and its data acquisition and controls systems provides a context for discussion of the requirements for each selection. Further framework is provided as upgrades to these systems accomplished in the 1990s and in 2003 are compared to demonstrate the role that technological advances have had in their improvement. Both of the selections were similar in their three phases; 1) definition of requirements, 2) identification of candidate products and their evaluation and testing and 3) selection by comparison of requirement fulfillment. The candidates for the communication architecture selection embraced several different methodologies which are explained and contrasted. Requirements for this selection are presented and the selection process is described. Several candidates for the software component of the data acquisition and controls system are identified, requirements for evaluation and selection are presented, and the evaluation process is described.

DECIPHERING THERMAL PHASE CURVES OF DRY, TIDALLY LOCKED TERRESTRIAL PLANETS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koll, Daniel D. B.; Abbot, Dorian S., E-mail: dkoll@uchicago.edu

2015-03-20

Next-generation space telescopes will allow us to characterize terrestrial exoplanets. To do so effectively it will be crucial to make use of all available data. We investigate which atmospheric properties can, and cannot, be inferred from the broadband thermal phase curve of a dry and tidally locked terrestrial planet. First, we use dimensional analysis to show that phase curves are controlled by six nondimensional parameters. Second, we use an idealized general circulation model to explore the relative sensitivity of phase curves to these parameters. We find that the feature of phase curves most sensitive to atmospheric parameters is the peak-to-troughmore » amplitude. Moreover, except for hot and rapidly rotating planets, the phase amplitude is primarily sensitive to only two nondimensional parameters: (1) the ratio of dynamical to radiative timescales and (2) the longwave optical depth at the surface. As an application of this technique, we show how phase curve measurements can be combined with transit or emission spectroscopy to yield a new constraint for the surface pressure and atmospheric mass of terrestrial planets. We estimate that a single broadband phase curve, measured over half an orbit with the James Webb Space Telescope, could meaningfully constrain the atmospheric mass of a nearby super-Earth. Such constraints will be important for studying the atmospheric evolution of terrestrial exoplanets as well as characterizing the surface conditions on potentially habitable planets.« less

Development of a Dynamic Time Sharing Scheduled Environment Final Report CRADA No. TC-824-94E

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jette, M.; Caliga, D.

Massively parallel computers, such as the Cray T3D, have historically supported resource sharing solely with space sharing. In that method, multiple problems are solved by executing them on distinct processors. This project developed a dynamic time- and space-sharing scheduler to achieve greater interactivity and throughput than could be achieved with space-sharing alone. CRI and LLNL worked together on the design, testing, and review aspects of this project. There were separate software deliverables. CFU implemented a general purpose scheduling system as per the design specifications. LLNL ported the local gang scheduler software to the LLNL Cray T3D. In this approach, processorsmore » are allocated simultaneously to aU components of a parallel program (in a “gang”). Program execution is preempted as needed to provide for interactivity. Programs are also reIocated to different processors as needed to efficiently pack the computer’s torus of processors. In phase one, CRI developed an interface specification after discussions with LLNL for systemlevel software supporting a time- and space-sharing environment on the LLNL T3D. The two parties also discussed interface specifications for external control tools (such as scheduling policy tools, system administration tools) and applications programs. CRI assumed responsibility for the writing and implementation of all the necessary system software in this phase. In phase two, CRI implemented job-rolling on the Cray T3D, a mechanism for preempting a program, saving its state to disk, and later restoring its state to memory for continued execution. LLNL ported its gang scheduler to the LLNL T3D utilizing the CRI interface implemented in phases one and two. During phase three, the functionality and effectiveness of the LLNL gang scheduler was assessed to provide input to CRI time- and space-sharing, efforts. CRI will utilize this information in the development of general schedulers suitable for other sites and future architectures.« less

Applications of active adaptive noise control to jet engines

NASA Technical Reports Server (NTRS)

Shoureshi, Rahmat; Brackney, Larry

1993-01-01

During phase 2 research on the application of active noise control to jet engines, the development of multiple-input/multiple-output (MIMO) active adaptive noise control algorithms and acoustic/controls models for turbofan engines were considered. Specific goals for this research phase included: (1) implementation of a MIMO adaptive minimum variance active noise controller; and (2) turbofan engine model development. A minimum variance control law for adaptive active noise control has been developed, simulated, and implemented for single-input/single-output (SISO) systems. Since acoustic systems tend to be distributed, multiple sensors, and actuators are more appropriate. As such, the SISO minimum variance controller was extended to the MIMO case. Simulation and experimental results are presented. A state-space model of a simplified gas turbine engine is developed using the bond graph technique. The model retains important system behavior, yet is of low enough order to be useful for controller design. Expansion of the model to include multiple stages and spools is also discussed.

Development Status of the Rad-Tolerant TTEthernet Controller

NASA Astrophysics Data System (ADS)

Fidi, Christian; van Masar, Ivan

2016-08-01

The use of switched networking technologies for aerospace and more recently automotive brings additional advantages for space applications like the increase in performance of the overall avionics of a spacecraft. These networks are characterized by a central device (switch) and a point-to-point structure between switch and terminal devices that eases electrical and logical insulation.However, for a use in highly-reliable or highly-available applications as in launchers or satellites systems, these network technologies need to provide built-in determinism and redundancy to fulfill the tight latency and jitter requirements of the avionics control loops and the respective hardware redundancy. Therefore a state of the art networking technology already provides these features and allows the modularity and scalability to be used for the different space applications and would allow combining the deterministic avionics with the high speed payload network in a spacecraft [1].Introducing the time-triggered principle to Ethernet allows combining the open industry standard IEE802.3 Ethernet currently use in almost all GSE platforms, with full control of latency and jitter of the time-triggered approach. To allow the time-triggered data flow over Ethernet, a network- wide synchronization time-base has to be established to allow deriving all network events on a globally known time which is typically done in software in almost all spacecrafts. The additional synchronization service of Time-triggered Ethernet has been implemented as additional quality of service (QoS) on layer 2 of the ISO/OSI network model and been standardized in the SAE AS6802 [3].Within a launcher, the communication system ensured the data exchanges between avionic functions during all phases of the launcher lifecycle which is composed of three areas: AIT operations, ground phase and flight phase. To ensure the use of a single network for the different phases, the network needs to support features like the handling of different traffic classes (critical traffic and non-critical traffic, i.e. TT, RC and BE [2]). Also the compatibility to the IEEE1588 synchronization protocol can be used to connect legacy IEEE1588 equipment for GSE equipment.However this commercially available technology currently used in the aviation-, the industrial- and the automotive market needs to be matured for the use in space applications. Therefore a development of the necessary space-grade components, mainly the switch and the end system is needed.This paper presents the current development status of a radiation tolerant integrated circuit for the use in different space applications. It outlines the different steps needed to be performed to ensure the usability of this digital chip in highly reliable as well as in highly available space applications.

Synthetic space with arbitrary dimensions in a few rings undergoing dynamic modulation

NASA Astrophysics Data System (ADS)

Yuan, Luqi; Xiao, Meng; Lin, Qian; Fan, Shanhui

2018-03-01

We show that a single ring resonator undergoing dynamic modulation can be used to create a synthetic space with an arbitrary dimension. In such a system, the phases of the modulation can be used to create a photonic gauge potential in high dimensions. As an illustration of the implication of this concept, we show that the Haldane model, which exhibits nontrivial topology in two dimensions, can be implemented in the synthetic space using three rings. Our results point to a route toward exploring higher-dimensional topological physics in low-dimensional physical structures. The dynamics of photons in such synthetic spaces also provides a mechanism to control the spectrum of light.

Rebuilding the space technology base

NASA Technical Reports Server (NTRS)

Povinelli, Frederick P.; Stephenson, Frank W.; Sokoloski, Martin M.; Montemerlo, Melvin D.; Venneri, Samuel L.; Mulville, Daniel R.; Hirschbein, Murray S.; Smith, Paul H.; Schnyer, A. Dan; Lum, Henry

1989-01-01

NASA's Civil Space Technology Initiative (CSTI) will not only develop novel technologies for space exploration and exploitation, but also take mature technologies into their demonstration phase in earth orbit. In the course of five years, CSTI will pay off in ground- and space-tested hardware, software, processes, methods for low-orbit transport and operation, and fundamental scientific research on the orbital environment. Attention is given to LOX/hydrogen and LOX/hydrocarbon reusable engines, liquid/solid fuel hybrid boosters, and aeroassist flight experiments for the validation of aerobraking with atmospheric friction. Also discussed are advanced scientific sensors, systems autonomy and telerobotics, control of flexible structures, precise segmented reflectors, high-rate high-capacity data handling, and advanced nuclear power systems.

Adsorption and Processes in Spacecraft Environmental Control and Life Support Systems

NASA Technical Reports Server (NTRS)

Dall-Bauman, Liese; Finn, John E.; Kliss, Mark (Technical Monitor)

1997-01-01

The environmental control and life support system on a spacecraft must maintain a safe and comfortable environment in which the crew can live and work. The system's functions include supplying the crew with oxygen and water, as well as removing carbon dioxide, water vapor, and trace contaminants from cabin air. Although open-loop systems have been used in the past, logistics and safety factors of current and future missions in space make near-complete recycling of the cabin's air and water desirable. The recycling process may include separation and reduction of carbon dioxide, removal of trace gas-phase contaminants, recovery and purification of humidity condensate, purification and polishing of wastewater streams, and other processes. Several of these operations can be performed totally or in part by adsorption processes. Adsorption processes are frequently good candidates for separation and purification in space by virtue of such characteristics as gravity independence, high reliability, relatively high energy efficiency, design flexibility, technological maturity, and regenerability. For these reasons, adsorption has historically played a key role in life support on U.S. and Russian piloted spacecraft. This article focuses on three current spacecraft life support applications that often use adsorption technology: carbon dioxide separation from cabin air, gas-phase trace contaminant control, and potable water recovery from waste streams. In each application, adsorption technology has been selected for use on the International Space Station. The requirements, science, and hardware for each application are discussed. Eventually, human space exploration may lead to construction of planetary habitats. These habitats may have additional applications, such as control of greenhouse gas composition and purification of hydroponic solutions, and may have different requirements and resources available to them, such as gases present in the planetary atmosphere. Adsorption separation and purification processes may continue to fulfill environmental control and life support needs well into the future.

Adsorption Processes in Spacecraft Environmental Control and Life Support Systems

NASA Technical Reports Server (NTRS)

Bauman, Liese Dall; Finn, John E.; Kliss, Mark (Technical Monitor)

1998-01-01

The environmental control and life support system on a spacecraft must maintain a safe and comfortable environment in which the crew can live and work. The system's functions include supplying the crew with oxygen and water as well as removing carbon dioxide, water vapor, and trace contaminants from cabin air. Although open-loop systems have been used in the past, logistics and safety factors of current and future missions in space make near-complete recycling of the cabin's air and water imperative. The recycling process may include separation and reduction of carbon dioxide, removal of trace gas-phase contaminants, recovery and purification of humidity condensate, purification and polishing of wastewater streams, and other processes. Several of these operations can be performed totally or in part by adsorption processes. These processes are frequently good candidates to perform separations and purifications in space due to their gravity independence, high reliability, relatively high energy efficiency, design flexibility, technological maturity, and regenerability. For these reasons, adsorption has historically played a key role in life support on U.S. and Russian piloted spacecraft. This article focuses on three current spacecraft life support applications that often use adsorption technology: gas-phase trace contaminant control, carbon dioxide removal from cabin air, and potable water recovery from waste streams. In each application, adsorption technology has been selected for use on the International Space Station. The requirements, science, and hardware for each of these applications are discussed. Eventually, human space exploration may lead to construction of planetary habitats. These habitats may provide additional opportunities for use of adsorption processes, such as control of greenhouse gas composition, and may have different requirements and resources available to them, such as gases present in the planetary atmosphere. Adsorption separation and purification processes can be expected to continue to fulfill environmental control and life support needs on future missions.

Flow Pattern Phenomena in Two-Phase Flow in Microchannels

NASA Astrophysics Data System (ADS)

Keska, Jerry K.; Simon, William E.

2004-02-01

Space transportation systems require high-performance thermal protection and fluid management techniques for systems ranging from cryogenic fluid management devices to primary structures and propulsion systems exposed to extremely high temperatures, as well as for other space systems such as cooling or environment control for advanced space suits and integrated circuits. Although considerable developmental effort is being expended to bring potentially applicable technologies to a readiness level for practical use, new and innovative methods are still needed. One such method is the concept of Advanced Micro Cooling Modules (AMCMs), which are essentially compact two-phase heat exchangers constructed of microchannels and designed to remove large amounts of heat rapidly from critical systems by incorporating phase transition. The development of AMCMs requires fundamental technological advancement in many areas, including: (1) development of measurement methods/systems for flow-pattern measurement/identification for two-phase mixtures in microchannels; (2) development of a phenomenological model for two-phase flow which includes the quantitative measure of flow patterns; and (3) database development for multiphase heat transfer/fluid dynamics flows in microchannels. This paper focuses on the results of experimental research in the phenomena of two-phase flow in microchannels. The work encompasses both an experimental and an analytical approach to incorporating flow patterns for air-water mixtures flowing in a microchannel, which are necessary tools for the optimal design of AMCMs. Specifically, the following topics are addressed: (1) design and construction of a sensitive test system for two-phase flow in microchannels, one which measures ac and dc components of in-situ physical mixture parameters including spatial concentration using concomitant methods; (2) data acquisition and analysis in the amplitude, time, and frequency domains; and (3) analysis of results including evaluation of data acquisition techniques and their validity for application in flow pattern determination.

14 CFR 437.69 - Communications.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Communications. 437.69 Section 437.69... TRANSPORTATION LICENSING EXPERIMENTAL PERMITS Safety Requirements § 437.69 Communications. (a) A permittee must be in communication with Air Traffic Control during all phases of flight. (b) A permittee must record...

14 CFR 437.69 - Communications.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Communications. 437.69 Section 437.69... TRANSPORTATION LICENSING EXPERIMENTAL PERMITS Safety Requirements § 437.69 Communications. (a) A permittee must be in communication with Air Traffic Control during all phases of flight. (b) A permittee must record...

14 CFR 437.69 - Communications.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Communications. 437.69 Section 437.69... TRANSPORTATION LICENSING EXPERIMENTAL PERMITS Safety Requirements § 437.69 Communications. (a) A permittee must be in communication with Air Traffic Control during all phases of flight. (b) A permittee must record...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akkelin, S.V.; Sinyukov, Yu.M.

A method allowing analysis of the overpopulation of phase space in heavy ion collisions in a model-independent way is proposed within the hydrodynamic approach. It makes it possible to extract a chemical potential of thermal pions at freeze-out, irrespective of the form of freeze-out (isothermal) hypersurface in Minkowski space and transverse flows on it. The contributions of resonance (with masses up to 2 GeV) decays to spectra, interferometry volumes, and phase-space densities are calculated and discussed in detail. The estimates of average phase-space densities and chemical potentials of thermal pions are obtained for SPS and RHIC energies. They demonstrate thatmore » multibosonic phenomena at those energies might be considered as a correction factor rather than as a significant physical effect. The analysis of the evolution of the pion average phase-space density in chemically frozen hadron systems shows that it is almost constant or slightly increases with time while the particle density and phase-space density at each space point decreases rapidly during the system's expansion. We found that, unlike the particle density, the average phase-space density has no direct link to the freeze-out criterion and final thermodynamic parameters, being connected rather to the initial phase-space density of hadronic matter formed in relativistic nucleus-nucleus collisions.« less

Labview Implementation of Image Processing and Phasing Control for the SIBOA Segmented Mirror Testbed

NASA Technical Reports Server (NTRS)

Partridge, James D.

2002-01-01

'NASA is preparing to launch the Next Generation Space Telescope (NGST). This telescope will be larger than the Hubble Space Telescope, be launched on an Atlas missile rather than the Space Shuttle, have a segmented primary mirror, and be placed in a higher orbit. All these differences pose significant challenges.' This effort addresses the challenge of implementing an algorithm for aligning the segments of the primary mirror during the initial deployment that was designed by Philip Olivier and members of SOMTC (Space Optics Manufacturing Technology Center). The implementation was to be performed on the SIBOA (Systematic Image Based Optical Alignment) test bed. Unfortunately, hardware/software aspect concerning SIBOA and an extended time period for algorithm development prevented testing before the end of the study period. Properties of the digital camera were studied and understood, resulting in the current ability of selecting optimal settings regarding saturation. The study was successful in manually capturing several images of two stacked segments with various relative phases. These images can be used to calibrate the algorithm for future implementation. Currently the system is ready for testing.

Otolithic and extraocular muscle proprioceptive influences on the spatial organization of the vestibulo- and cervico-ocular quick phases.

PubMed

Pettorossi, V E; Manni, E; Errico, P; Ferraresi, A; Bortolami, R

1997-03-01

The cervico-ocular reflex (COR) was studied alone or in combination with the vestibulo-ocular reflex (VOR) in the rabbit. Step stimulations of the body with respect to the fixed head induced small slow compensatory responses followed by large compensatory quick phases (QP). These responses remained aligned with the horizon at different head pitch angles. The QP reorientation in space was due to the gravity influence on the otolithic receptors. The vestibular induced QPs exhibit a similar pattern. Because of this reorientation, the reduction of the amplitude of the vestibular induced QPs, due to the addition of the COR, was maintained even at different static head positions. The electrolytic lesion of the ophthalmic branch of the trigeminal nerve deeply affected the space orientation of the COR. In particular, the cervically induced compensatory QPs of the eye ipsilateral to the lesion showed a remarkable variability of their trajectories and they lost space reorientation. These findings suggest that the coordinate system controlling the QPs is influenced by signals originating from both head position in space and eye position in the orbit.

Fundamental performance determining factors of the ultrahigh-precision space-borne optical metrology system for the LISA Pathfinder mission

NASA Astrophysics Data System (ADS)

Hechenblaikner, Gerald; Flatscher, Reinhold

2013-05-01

The LISA Pathfinder mission to space employs an optical metrology system (OMS) at its core to measure the distance and attitude between two freely floating test-masses to picometer and nanorad accuracy, respectively, within the measurement band of [1 mHz, 30 mHz]. The OMS is based upon an ultra-stable optical bench with 4 heterodyne interferometers from which interference signals are read-out and processed by a digital phase-meter. Laser frequency noise, power fluctuations and optical path-length variations are suppressed to uncritical levels by dedicated control loops so that the measurement performance approaches the sensor limit imposed by the phasemeter. The system design is such that low frequency common mode noise which affects the read-out phase of all four interferometers is generally well suppressed by subtraction of a reference phase from the other interferometer signals. However, high frequency noise directly affects measurement performance and its common mode rejection depends strongly on the relative signal phases. We discuss how the data from recent test campaigns point towards high frequency phase noise as a likely performance limiting factor which explains some important performance features.

Disentangling the Cosmic Web with Lagrangian Submanifold

NASA Astrophysics Data System (ADS)

Shandarin, Sergei F.; Medvedev, Mikhail V.

2016-10-01

The Cosmic Web is a complicated highly-entangled geometrical object. Remarkably it has formed from practically Gaussian initial conditions, which may be regarded as the simplest departure from exactly uniform universe in purely deterministic mapping. The full complexity of the web is revealed neither in configuration no velocity spaces considered separately. It can be fully appreciated only in six-dimensional (6D) phase space. However, studies of the phase space is complicated by the fact that every projection of it on a three-dimensional (3D) space is multivalued and contained caustics. In addition phase space is not a metric space that complicates studies of geometry. We suggest to use Lagrangian submanifold i.e., x = x(q), where both x and q are 3D vectors instead of the phase space for studies the complexity of cosmic web in cosmological N-body dark matter simulations. Being fully equivalent in dynamical sense to the phase space it has an advantage of being a single valued and also metric space.

Practical Methodology for the Inclusion of Nonlinear Slosh Damping in the Stability Analysis of Liquid-Propelled Space Vehicles

NASA Technical Reports Server (NTRS)

Ottander, John A.; Hall, Robert A.; Powers, Joseph F.

2017-01-01

One of the challenges of developing flight control systems for liquid-propelled space vehicles is ensuring stability and performance in the presence of parasitic minimally damped slosh dynamics in the liquid propellants. This can be especially difficult when the fundamental frequencies of the slosh motions are in proximity to the frequency used for vehicle control. The challenge is partially alleviated since the energy dissipation and effective damping in the slosh modes increases with amplitude. However, traditional launch vehicle control design methodology is performed with linearized systems using a fixed slosh damping corresponding to a slosh motion amplitude based on heritage values. This papers presents a method for performing the control design and analysis using damping at slosh amplitudes chosen based on the resulting limit cycle amplitude of the vehicle thrust vector system due to a control-slosh interaction under degraded phase and gain margin conditions.

Practical Methodology for the Inclusion of Nonlinear Slosh Damping in the Stability Analysis of Liquid-propelled Space Vehicles

NASA Technical Reports Server (NTRS)

Ottander, John A.; Hall, Robert A., Jr.; Powers, Joseph F.

2017-01-01

One of the challenges of developing flight control systems for liquid-propelled space vehicles is ensuring stability and performance in the presence of parasitic minimally damped slosh dynamics in the liquid propellants. This can be especially difficult when the fundamental frequencies of the slosh motions are in proximity to the frequency used for vehicle control. The challenge is partially alleviated since the energy dissipation and effective damping in the slosh modes increases with amplitude. However, traditional launch vehicle control design methodology is performed with linearized systems using a fixed slosh damping corresponding to a slosh motion amplitude based on heritage values. This papers presents a method for performing the control design and analysis using damping at slosh amplitudes chosen based on the resulting limit cycle amplitude of the vehicle thrust vector system due to a control-slosh interaction under degraded phase and gain margin conditions.

Bifurcation and Fractal of the Coupled Logistic Map

NASA Astrophysics Data System (ADS)

Wang, Xingyuan; Luo, Chao

The nature of the fixed points of the coupled Logistic map is researched, and the boundary equation of the first bifurcation of the coupled Logistic map in the parameter space is given out. Using the quantitative criterion and rule of system chaos, i.e., phase graph, bifurcation graph, power spectra, the computation of the fractal dimension, and the Lyapunov exponent, the paper reveals the general characteristics of the coupled Logistic map transforming from regularity to chaos, the following conclusions are shown: (1) chaotic patterns of the coupled Logistic map may emerge out of double-periodic bifurcation and Hopf bifurcation, respectively; (2) during the process of double-period bifurcation, the system exhibits self-similarity and scale transform invariability in both the parameter space and the phase space. From the research of the attraction basin and Mandelbrot-Julia set of the coupled Logistic map, the following conclusions are indicated: (1) the boundary between periodic and quasiperiodic regions is fractal, and that indicates the impossibility to predict the moving result of the points in the phase plane; (2) the structures of the Mandelbrot-Julia sets are determined by the control parameters, and their boundaries have the fractal characteristic.

Phase space methods in HMD systems

NASA Astrophysics Data System (ADS)

Babington, James

2017-06-01

We consider using phase space techniques and methods in analysing optical ray propagation in head mounted display systems. Two examples are considered that illustrate the concepts and methods. Firstly, a shark tooth freeform geometry, and secondly, a waveguide geometry that replicates a pupil in one dimension. Classical optics and imaging in particular provide a natural stage to employ phase space techniques, albeit as a constrained system. We consider how phase space provides a global picture of the physical ray trace data. As such, this gives a complete optical world history of all of the rays propagating through the system. Using this data one can look at, for example, how aberrations arise on a surface by surface basis. These can be extracted numerically from phase space diagrams in the example of a freeform imaging prism. For the waveguide geometry, phase space diagrams provide a way of illustrating how replicated pupils behave and what these imply for design considerations such as tolerances.

NASA/DOD (National Aeronautics and Space Administration/Department of Defense) Control/Structures Interaction Technology Conference (2nd) Held in Colorado Springs, Colorado on 17-19 November 1987.

DTIC Science & Technology

1988-06-01

James McKelvy and Harold Tinsley *," . CONCEPTUAL DESIGN OF A SPACE STATION DYNAMIC SCALE MODEL ............. 87 Robert Letchworth, Paul E... CONCEPTUAL SYSTEM DESIGN FOR ANTENNA THERMAL AND DYNAMIC DISTORTION COMPENSATION USING A PHASED ARRAY FEED ................... 145 G. R. Sharp, R. J...to achieve somne desired state or trajectory. For conceptual purposes, however, an alternate view is useful in which the measurement reference against

KSC-2014-3536

NASA Image and Video Library

2014-08-15

CAPE CANAVERAL, Fla. – Kennedy Space Center Director and former astronaut Bob Cabana, talks to Florida middle school students and their teachers during the Zero Robotics finals competition at the center's Space Station Processing Facility in Florida. Students designed software to control Synchronized Position Hold Engage and Reorient Experimental Satellites, or SPHERES, and competed with other teams locally. The Zero Robotics is a robotics programming competition where the robots are SPHERES. The competition starts online, where teams program the SPHERES to solve an annual challenge. After several phases of virtual competition in a simulation environment that mimics the real SPHERES, finalists are selected to compete in a live championship aboard the space station. Students compete to win a technically challenging game by programming their strategies into the SPHERES satellites. The programs are autonomous and the students cannot control the satellites during the test. Photo credit: NASA/Daniel Casper

KSC-2014-3535

NASA Image and Video Library

2014-08-15

CAPE CANAVERAL, Fla. – Kennedy Space Center Director and former astronaut Bob Cabana, talks to Florida middle school students and their teachers during the Zero Robotics finals competition at the center's Space Station Processing Facility in Florida. Students designed software to control Synchronized Position Hold Engage and Reorient Experimental Satellites, or SPHERES, and competed with other teams locally. The Zero Robotics is a robotics programming competition where the robots are SPHERES. The competition starts online, where teams program the SPHERES to solve an annual challenge. After several phases of virtual competition in a simulation environment that mimics the real SPHERES, finalists are selected to compete in a live championship aboard the space station. Students compete to win a technically challenging game by programming their strategies into the SPHERES satellites. The programs are autonomous and the students cannot control the satellites during the test. Photo credit: NASA/Daniel Casper

KSC-2014-3537

NASA Image and Video Library

2014-08-15

CAPE CANAVERAL, Fla. – Kennedy Space Center Director and former astronaut Bob Cabana, talks to Florida middle school students and their teachers during the Zero Robotics finals competition at the center's Space Station Processing Facility in Florida. Students designed software to control Synchronized Position Hold Engage and Reorient Experimental Satellites, or SPHERES, and competed with other teams locally. The Zero Robotics is a robotics programming competition where the robots are SPHERES. The competition starts online, where teams program the SPHERES to solve an annual challenge. After several phases of virtual competition in a simulation environment that mimics the real SPHERES, finalists are selected to compete in a live championship aboard the space station. Students compete to win a technically challenging game by programming their strategies into the SPHERES satellites. The programs are autonomous and the students cannot control the satellites during the test. Photo credit: NASA/Daniel Casper

Electric motor designs for attenuating torque disturbance in sensitive space mechanisms

NASA Astrophysics Data System (ADS)

Marks, David B.; Fink, Richard A.

2003-09-01

When a motion control system introduces unwanted torque jitter and motion anomalies into sensitive space flight optical or positioning mechanisms, the pointing accuracy, positioning capability, or scanning resolution of the mission suffers. Special motion control technology must be employed to provide attenuation of the harmful torque disturbances. Brushless DC (BLDC) Motors with low torque disturbance characteristics have been successfully used on such notable missions as the Hubble Space Telescope when conventional approaches to motor design would not work. Motor designs for low disturbance mechanisms can include two and three phase sinusoidal BLDC motors, BLDC motors without iron teeth, and sometimes skewed or non-integral slot designs for motors commutated with Hall effect devices. The principal components of motor torque disturbance, successful BLDC motor designs for attenuating disturbances, and design trade-offs for optimum performance are examined.

Phase Change Fabrics Control Temperature

NASA Technical Reports Server (NTRS)

2009-01-01

Originally featured in Spinoff in 1997, Outlast Technologies Inc. (formerly Gateway Technologies Inc.) has built its entire product line on microencapsulated phase change materials, developed in Small Business Innovation Research (SBIR) contracts with Johnson Space Center after initial development for the U.S. Air Force. The Boulder, Colorado-based company acquired the exclusive patent rights and now integrates these materials into textiles or onto finished apparel, providing temperature regulation in bedding materials and a full line of apparel for both ordinary and extreme conditions.

Zero-Boil-Off Tank (ZBOT) Experiment: Ground-Based Validation of Self-Pressurization and Pressure Control Two-Phase CFD Model

NASA Technical Reports Server (NTRS)

Kassemi, Mohammad; Hylton, Sonya; Kartuzova, Olga

2017-01-01

Integral to all phases of NASA's projected space and planetary expeditions is affordable and reliable cryogenic fluid storage for use in propellant or life support systems. Cryogen vaporization due to heat leaks into the tank from its surroundings and support structure can cause self-pressurization relieved through venting. This has led to a desire to develop innovative pressure control designs based on mixing of the bulk tank fluid together with some form of active or passive cooling to allow storage of the cryogenic fluid with zero or reduced boil-off. The Zero-Boil-Off Tank (ZBOT) Experiments are a series of small scale tank pressurization and pressure control experiments aboard the International Space Station (ISS) that use a transparent volatile simulant fluid in a transparent sealed tank to delineate various fundamental fluid flow, heat and mass transport, and phase change phenomena that control storage tank pressurization and pressure control in microgravity. The hardware for ZBOT-1 flew to ISS on the OA-7 flight in April 2017 and operations are planned to begin in September 2017, encompassing more than 90 tests. This paper presents preliminary results from ZBOT's ground-based research delineating both pressurization and pressure reduction trends in the sealed test tank. Tank self-pressurization tests are conducted under three modes: VJ heating, strip heating and simultaneous VJ and strip heating in attempt to simulate heat leaks from the environment, the support structure and both. The jet mixing pressure control studies are performed either from an elevated uniform temperature condition or from thermally stratified conditions following a self-pressurization run. Jet flow rates are varied from 2-25 cm/s spanning a range of jet Re number in laminar, transitional, and turbulent regimes and a range of Weber numbers covering no ullage penetration, partial penetration and complete ullage penetration and break-up (only in microgravity). Numerical prediction of a two-phase CFD model are compared to experimental 1g results to both validate the model and also indicate the effect of the residual non-condensable gas on evolution of pressure and temperature distributions in the tank during pressurization and pressure control.

US-Korea Nanotechnology, Biotechnology, and Information Technology (NBIT) Symbiosys Program - Phase 1

DTIC Science & Technology

2010-10-01

diameter, length, and spacing. Fabrication Technology: Synthesis of self-organized AAO ( Anodic aluminum oxide ) templates with controlled diameter...nanowires arrayed in anodized aluminum oxide ( AAO ) templates and the diameter is precisely controlled by using atomic layer deposition (ALD) process...Jin, “Highly Self-assembled Nanotubular Aluminum Oxide by Hard Anodization ”, J. Mater. Res. (in press, December 2010). 3. J.Y. Kim, K. Noh, C. Choi

Hardware-In-The-Loop Testing of Continuous Control Algorithms for a Precision Formation Flying Demonstration Mission

NASA Technical Reports Server (NTRS)

Naasz, Bo J.; Burns, Richard D.; Gaylor, David; Higinbotham, John

2004-01-01

A sample mission sequence is defined for a low earth orbit demonstration of Precision Formation Flying (PFF). Various guidance navigation and control strategies are discussed for use in the PFF experiment phases. A sample PFF experiment is implemented and tested in a realistic Hardware-in-the-Loop (HWIL) simulation using the Formation Flying Test Bed (FFTB) at NASA's Goddard Space Flight Center.

Accommodation of practical constraints by a linear programming jet select. [for Space Shuttle

NASA Technical Reports Server (NTRS)

Bergmann, E.; Weiler, P.

1983-01-01

An experimental spacecraft control system will be incorporated into the Space Shuttle flight software and exercised during a forthcoming mission to evaluate its performance and handling qualities. The control system incorporates a 'phase space' control law to generate rate change requests and a linear programming jet select to compute jet firings. Posed as a linear programming problem, jet selection must represent the rate change request as a linear combination of jet acceleration vectors where the coefficients are the jet firing times, while minimizing the fuel expended in satisfying that request. This problem is solved in real time using a revised Simplex algorithm. In order to implement the jet selection algorithm in the Shuttle flight control computer, it was modified to accommodate certain practical features of the Shuttle such as limited computer throughput, lengthy firing times, and a large number of control jets. To the authors' knowledge, this is the first such application of linear programming. It was made possible by careful consideration of the jet selection problem in terms of the properties of linear programming and the Simplex algorithm. These modifications to the jet select algorithm may by useful for the design of reaction controlled spacecraft.

The role of reminding in the effects of spaced repetitions on cued recall: sufficient but not necessary.

PubMed

Wahlheim, Christopher N; Maddox, Geoffrey B; Jacoby, Larry L

2014-01-01

Three experiments examined the role of study-phase retrieval (reminding) in the effects of spaced repetitions on cued recall. Remindings were brought under task control to evaluate their effects. Participants studied 2 lists of word pairs containing 3 item types: single items that appeared once in List 2, within-list repetitions that appeared twice in List 2, and between-list repetitions that appeared once in List 1 and once in List 2. Our primary interest was in performance on between-list repetitions. Detection of between-list repetitions was encouraged in an n-back condition by instructing participants to indicate when a presented item was a repetition of any preceding item, including items presented in List 1. In contrast, detection of between-list repetitions was discouraged in a within-list back condition by instructing participants only to indicate repetitions occurring in List 2. Cued recall of between-list repetitions was enhanced when instructions encouraged detection of List 1 presentations. These results accord with those from prior experiments showing a role of study-phase retrieval in effects of spacing repetitions. Past experiments have relied on conditionalized data to draw conclusions, producing the possibility that performance benefits merely reflected effects of item selection. By bringing effects under task control, we avoided that problem. Our results provide evidence that reminding resulting from retrieval of earlier presentations plays a role in the effects of spaced repetitions on cued recall. However, our results also reveal that such retrievals are not necessary to produce an effect of spacing repetitions.

The Role of Reminding in the Effects of Spaced Repetitions on Cued Recall: Sufficient but not Necessary

PubMed Central

Wahlheim, Christopher N.; Maddox, Geoffrey B.; Jacoby, Larry L.

2014-01-01

Three experiments examined the role of study-phase retrieval (reminding) in the effects of spaced repetitions on cued recall. Remindings were brought under task control to evaluate their effects. Participants studied two lists of word pairs containing three item types: single items that appeared once in List 2, within-list repetitions that appeared twice in List 2, and between-list repetitions that appeared once in List 1 and once in List 2. Our primary interest was in performance on between-list repetitions. Detection of between-list repetitions was encouraged in an n-back condition by instructing participants to indicate when a presented item was a repetition of any preceding item, including items presented in List 1. In contrast, detection of between-list repetitions was discouraged in a within-list back condition by instructing participants only to indicate repetitions occurring in List 2. Cued recall of between-list repetitions was enhanced when instructions encouraged detection of List 1 presentations. These results accord with those from prior experiments showing a role of study-phase retrieval in effects of spacing repetitions. Past experiments have relied on conditionalized data to draw conclusions, producing the possibility that performance benefits merely reflected effects of item selection. By bringing effects under task control, we avoided that problem. Our results provide evidence that reminding resulting from retrieval of earlier presentations plays a role in the effects of spaced repetitions on cued recall. However, our results also reveal that such retrievals are not necessary to produce an effect of spacing repetitions. PMID:23937236

Fiber-based coherent polarization beam combining with cascaded phase-locking and polarization-transforming controls

NASA Astrophysics Data System (ADS)

Yang, Yan; Geng, Chao; Li, Feng; Huang, Guan; Li, Xinyang

2018-05-01

In this paper, the fiber-based coherent polarization beam combining (CPBC) with cascaded phase-locking (PL) and polarization-transforming (PT) controls was proposed to combine imbalanced input beams where the number of the input beams is not binary, in which the PL control was performed using the piezoelectric-ring fiber-optic phase compensator, and the PT control was realized by the dynamic polarization controller, simultaneously. The principle of the proposed CPBC was introduced. The performance of the proposed CPBC was analyzed in comparison with the CPBC based on PL control and the CPBC based on PT control. The basic experiment of CPBC of three laser beams was carried out to validate the feasibility of the proposed CPBC, where cascaded controls of PL and PT were implemented based on stochastic parallel gradient descent algorithm. Simulation and experimental results show that the proposed CPBC incorporates the advantages of the two previous CPBC schemes and performs well in the closed loop. Moreover, the expansibility and the application of the proposed CPBC were validated by scaling the CPBC to combine seven laser beams. We believe that the proposed fiber-based CPBC with cascaded PL and PT controls has great potential in free space optical communications employing the multi-aperture receiver with asymmetric structure.

Dynamic optical arbitrary waveform shaping based on cascaded optical modulators of single FBG.

PubMed

Chen, Jingyuan; Li, Peili

2015-08-10

A dynamic optical arbitrary waveform generation (O-AWG) with amplitude and phase independently controlled in optical modulators of single fiber Bragg Grating (FBG) has been proposed. This novel scheme consists of several optical modulators. In the optical modulator (O-MOD), a uniform FBG is used to filter spectral component of the input signal. The amplitude is controlled by fiber stretcher (FS) in Mach-Zehnder interference (MZI) structure through interference of two MZI arms. The phase is manipulated via the second FS in the optical modulator. This scheme is investigated by simulation. Consequently, optical pulse trains with different waveforms as well as pulse trains with nonuniform pulse intensity, pulse spacing and pulse width within each period are obtained through FSs adjustment to alter the phase shifts of signal in each O-MOD.

A gradient field defeats the inherent repulsion between magnetic nanorods

PubMed Central

Gu, Yu; Burtovyy, Ruslan; Custer, John; Luzinov, Igor; Kornev, Konstantin G.

2014-01-01

When controlling the assembly of magnetic nanorods and chains of magnetic nanoparticles, it is extremely challenging to bring them together side by side while keeping a desired spacing between their axes. We show that this challenge can be successfully resolved by using a non-uniform magnetic field that defeats an inherent repulsion between nanorods. Nickel nanorods were suspended in a viscous film and a non-uniform field was used to control their placement. The in-plane movement of nanorods was tracked with a high-speed camera and a detailed image analysis was conducted to quantitatively characterize the behaviour of the nanorods. The analysis focused on the behaviour of a pair of neighbour nanorods, and a corresponding dynamic model was formulated and investigated. The complex two-dimensional dynamics of a nanorod pair was analysed analytically and numerically, and a phase portrait was constructed. Using this phase portrait, we classified the nanorod behaviour and revealed the experimental conditions in which nanorods could be placed side by side. Dependence of the distance between a pair of neighbour nanorods on physical parameters was analysed. With the aid of the proposed theory, one can build different lattices and control their spacing by applying different field gradients. PMID:26064550

Mechanically tunable actin networks using programmable DNA based cross-linkers

NASA Astrophysics Data System (ADS)

Schnauss, Joerg; Lorenz, Jessica; Schuldt, Carsten; Kaes, Josef; Smith, David

Cells employ multiple cross-linkers with very different properties. Studies of the entire phase space, however, were infeasible since they were restricted to naturally occurring cross-linkers. These components cannot be controllably varied and differ in many parameters. We resolve this limitation by forming artificial actin cross-linkers, which can be controllably varied. The basic building block is DNA enabling a well-defined length variation. DNA can be attached to actin binding peptides with known binding affinities. We used bulk rheology to investigate mechanical properties of these networks. We were able to reproduce mechanical features of actin networks cross-linked by fascin by using a short version of our artificial complex with a high binding affinity. Additionally, we were able to resemble findings for the cross-linker alpha-actinin by employing a long cross-linker with a low binding affinity. Between these natural limits we investigated three different cross-linker lengths each with two different binding affinities. With these controlled variations we are able to precisely screen the phase space of cross-linked actin networks by changing only one specific parameter and not the entire set of properties as in the case of naturally occurring cross-linking complexes.

Intellectual Performance as a Function of Repression and Menstrual Cycle.

ERIC Educational Resources Information Center

Englander-Golden, Paula; And Others

Performance on complex (Space Relations and Verbal Reasoning) and simple (Digit Symbol) tests was investigated as a function of Byrne's Repression-Sensitization (RS) dimension, phase of menstrual cycle and premenstrual-menstrual (PM) symptomatology in a group of females not taking oral contraceptives. Two control groups, consisting of males and…

Modular space station phase B extension, preliminary system design. Volume 4: Subsystems analyses

NASA Technical Reports Server (NTRS)

Antell, R. W.

1972-01-01

The subsystems tradeoffs, analyses, and preliminary design results are summarized. Analyses were made of the structural and mechanical, environmental control and life support, electrical power, guidance and control, reaction control, information, and crew habitability subsystems. For each subsystem a summary description is presented including subsystem requirements, subsystem description, and subsystem characteristics definition (physical, performance, and interface). The major preliminary design data and tradeoffs or analyses are described in detail at each of the assembly levels.

Modular space station phase B extension preliminary systems design report. Volume 6: Trades and analyses

NASA Technical Reports Server (NTRS)

Jones, A. L.

1972-01-01

Requirements and concepts and the tradeoff analysis leading to the preferred concept are presented. Integrated analyses are given for subsystems and thermal control. Specific tradeoffs and analyses are also given for water management, atmosphere control, energy storage, radiators, navigation, control moment gyros, and system maintenance. The analyses of manipulator concepts and requirements, and supplemental analyses of information management issues are summarized. Subsystem reliability analyses include a detailed discussion of the critical failure analysis.

Development of a laboratory prototype spraying flash evaporator.

NASA Technical Reports Server (NTRS)

Gaddis, J. L.

1972-01-01

A functional description of the flash evaporator that is being developed as a candidate for the Space Shuttle Environmental Control System thermal control is presented. A single evaporator configuration uses water as an evaporant to accommodate on-orbit peak heat loads and Freon 22 for terrestrial flight phases below 120,000 ft altitude. Development history, test plans, and operational characteristics are described. Detailed information is included to show: design features, fabrication techniques used for a prototype unit, redundancy considerations, and the control arrangement.

On the importance of an accurate representation of the initial state of the system in classical dynamics simulations

NASA Astrophysics Data System (ADS)

García-Vela, A.

2000-05-01

A definition of a quantum-type phase-space distribution is proposed in order to represent the initial state of the system in a classical dynamics simulation. The central idea is to define an initial quantum phase-space state of the system as the direct product of the coordinate and momentum representations of the quantum initial state. The phase-space distribution is then obtained as the square modulus of this phase-space state. The resulting phase-space distribution closely resembles the quantum nature of the system initial state. The initial conditions are sampled with the distribution, using a grid technique in phase space. With this type of sampling the distribution of initial conditions reproduces more faithfully the shape of the original phase-space distribution. The method is applied to generate initial conditions describing the three-dimensional state of the Ar-HCl cluster prepared by ultraviolet excitation. The photodissociation dynamics is simulated by classical trajectories, and the results are compared with those of a wave packet calculation. The classical and quantum descriptions are found in good agreement for those dynamical events less subject to quantum effects. The classical result fails to reproduce the quantum mechanical one for the more strongly quantum features of the dynamics. The properties and applicability of the phase-space distribution and the sampling technique proposed are discussed.

Performance Assessment in the PILOT Experiment On Board Space Stations Mir and ISS.

PubMed

Johannes, Bernd; Salnitski, Vyacheslav; Dudukin, Alexander; Shevchenko, Lev; Bronnikov, Sergey

2016-06-01

The aim of this investigation into the performance and reliability of Russian cosmonauts in hand-controlled docking of a spacecraft on a space station (experiment PILOT) was to enhance overall mission safety and crew training efficiency. The preliminary findings on the Mir space station suggested that a break in docking training of about 90 d significantly degraded performance. Intensified experiment schedules on the International Space Station (ISS) have allowed for a monthly experiment using an on-board simulator. Therefore, instead of just three training tasks as on Mir, five training flights per session have been implemented on the ISS. This experiment was run in parallel but independently of the operational docking training the cosmonauts receive. First, performance was compared between the experiments on the two space stations by nonparametric testing. Performance differed significantly between space stations preflight, in flight, and postflight. Second, performance was analyzed by modeling the linear mixed effects of all variances (LME). The fixed factors space station, mission phases, training task numbers, and their interaction were analyzed. Cosmonauts were designated as a random factor. All fixed factors were found to be significant and the interaction between stations and mission phase was also significant. In summary, performance on the ISS was shown to be significantly improved, thus enhancing mission safety. Additional approaches to docking performance assessment and prognosis are presented and discussed.

Shortcuts to adiabaticity by counterdiabatic driving for trapped-ion displacement in phase space

PubMed Central

An, Shuoming; Lv, Dingshun; del Campo, Adolfo; Kim, Kihwan

2016-01-01

The application of adiabatic protocols in quantum technologies is severely limited by environmental sources of noise and decoherence. Shortcuts to adiabaticity by counterdiabatic driving constitute a powerful alternative that speed up time-evolution while mimicking adiabatic dynamics. Here we report the experimental implementation of counterdiabatic driving in a continuous variable system, a shortcut to the adiabatic transport of a trapped ion in phase space. The resulting dynamics is equivalent to a ‘fast-motion video' of the adiabatic trajectory. The robustness of this protocol is shown to surpass that of competing schemes based on classical local controls and Fourier optimization methods. Our results demonstrate that shortcuts to adiabaticity provide a robust speedup of quantum protocols of wide applicability in quantum technologies. PMID:27669897

Autonomous integrated GPS/INS navigation experiment for OMV. Phase 1: Feasibility study

NASA Technical Reports Server (NTRS)

Upadhyay, Triveni N.; Priovolos, George J.; Rhodehamel, Harley

1990-01-01

The phase 1 research focused on the experiment definition. A tightly integrated Global Positioning System/Inertial Navigation System (GPS/INS) navigation filter design was analyzed and was shown, via detailed computer simulation, to provide precise position, velocity, and attitude (alignment) data to support navigation and attitude control requirements of future NASA missions. The application of the integrated filter was also shown to provide the opportunity to calibrate inertial instrument errors which is particularly useful in reducing INS error growth during times of GPS outages. While the Orbital Maneuvering Vehicle (OMV) provides a good target platform for demonstration and for possible flight implementation to provide improved capability, a successful proof-of-concept ground demonstration can be obtained using any simulated mission scenario data, such as Space Transfer Vehicle, Shuttle-C, Space Station.

Jet mixing in low gravity - Results of the Tank Pressure Control Experiment

NASA Technical Reports Server (NTRS)

Bentz, M. D.; Meserole, J. S.; Knoll, R. H.

1992-01-01

The Tank Pressure Control Experiment (TPCE) is discussed with attention given to the results for controlling storage-tank pressures by forced-convective mixing in microgravitational environments. The fluid dynamics of cryogenic fluids in space is simulated with freon-113 during axial-jet-induced mixing. The experimental flow-pattern data are found to confirm previous data as well as existing mixing correlations. Thermal nonuniformities and tank pressure can be reduced by employing low-energy mixing jets which are useful for enhancing heat/mass transfer between phases. It is found that space cryogenic systems based on the principle of active mixing can be more reliable and predictable than other methods, and continuous or periodic mixing can be accomplished with only minor energy addition to the fluid.

Re-Engineering of the Hubble Space Telescope (HST) to Reduce Operational Costs

NASA Technical Reports Server (NTRS)

Garvis, Michael; Dougherty, Andrew; Whittier, Wallace

1996-01-01

Satellite telemetry processing onboard the Hubble Space Telescope (HST) is carried out using dedicated software and hardware. The current ground system is expensive to operate and maintain. The mandate to reduce satellite ground system operations and maintenance costs by the year 2000 led NASA to upgrade the command and control systems in order to improve the data processing capabilities, reduce operator experience levels and increase system standardization. As a result, a command and control system product development team was formed to redesign and develop the HST ground system. The command and control system ground system development consists of six elements. The results of the prototyping phase carried out for the following of these elements are presented: the front end processor; middleware, and the graphical user interface.

GFAST Software Demonstration

NASA Image and Video Library

2017-03-17

NASA engineers and test directors gather in Firing Room 3 in the Launch Control Center at NASA's Kennedy Space Center in Florida, to watch a demonstration of the automated command and control software for the agency's Space Launch System (SLS) and Orion spacecraft. In front, far right, is Charlie Blackwell-Thompson, launch director for Exploration Mission 1 (EM-1). The software is called the Ground Launch Sequencer. It will be responsible for nearly all of the launch commit criteria during the final phases of launch countdowns. The Ground and Flight Application Software Team (GFAST) demonstrated the software. It was developed by the Command, Control and Communications team in the Ground Systems Development and Operations (GSDO) Program. GSDO is helping to prepare the center for the first test flight of Orion atop the SLS on EM-1.

Cryogenic temperature control by means of energy storage materials. [for long space voyages

NASA Technical Reports Server (NTRS)

Grodzka, P. G.; Picklesimer, E. A.; Connor, L. E.

1977-01-01

An investigation was conducted to study the concept of thermal control by means of physical or chemical reaction heats for applications involving the storage of cryogens during long-term space voyages. The investigation included some preliminary experimental tests of energy storage material (ESM) effectiveness. The materials considered can store and liberate large amounts of thermal energy by means of mechanisms such as sensible heat, heat of fusion, and physical or chemical reaction heat. A differential thermal analysis was utilized in the laboratory tests. Attention is given to the evaluation of cryogenic ESM thermal control concepts, the experimental determination of phase change materials characteristics, and adsorption ESMs. It is found that an ESM shield surrounded by multiple layer insulation provides the best protection for a cryogen store.

WISPER: Wirless Space Power Experiment

NASA Technical Reports Server (NTRS)

Hawkins, Joseph

1993-01-01

The 1993 Advanced Design Project at the University of Alaska Fairbanks was to design a spacecraft as a technology demonstration of wireless power transmission (WPT). With cost effectiveness as a design constraint, a micro-satellite in low earth orbit (LEO) was chosen for the mission. Existing and near term technologies were analyzed and selected for the project. In addition to the conceptual design of the payload, support systems, and structure, the analysis included attention to safety, environmental impact, cost, and schedule for construction and operation. Wireless power beaming is not a new concept. Experimental demonstrations and study efforts have continued since the early 1960's. With the latest progress in transmitter and receiver technology, the next natural step is to beam power from earth to space. This proposed flight demonstration will advance the science of power beaming and prove the viability of various applications of WPT in space. Two methods of power beaming will be examined during the two separate phases of the spacecraft life. The first phase will demonstrate the technology and examine the theory of microwave power transmission at a high frequency. Special aspects of the first phase will include a highly accurate attitude control system and a 14 m inflatable parabolic antenna. The second phase will investigate the utilization of high intensity laser power using modified photovoltaic arrays. Special instrumentation on the spacecraft will measure the conversion efficiency from the received microwave or laser power to direct current power.

VCO PLL Frequency Synthesizers for Spacecraft Transponders

NASA Technical Reports Server (NTRS)

Smith, Scott; Mysoor, Narayan; Lux, James; Cook, Brian

2007-01-01

Two documents discuss a breadboard version of advanced transponders that, when fully developed, would be installed on future spacecraft to fly in deep space. These transponders will be required to be capable of operation on any deepspace- communications uplink frequency channel between 7,145 and 7,235 MHz, and any downlink frequency channel between 8,400 and 8,500 MHz. The document focuses on the design and operation of frequency synthesizers for the receiver and transmitter. Heretofore, frequency synthesizers in deep-space transponders have been based on dielectric resonator oscillators (DROs), which do not have the wide tuning bandwidth necessary to tune over all channels in the uplink or downlink frequency bands. To satisfy the requirement for tuning bandwidth, the present frequency synthesizers are based on voltage-controlled-oscillator (VCO) phase-locked loops (PLLs) implemented by use of monolithic microwave integrated circuits (MMICs) implemented using inGaP heterojunction bipolar transistor (HBT) technology. MMIC VCO PLL frequency synthesizers similar to the present ones have been used in commercial and military applications but, until now, have exhibited too much phase noise for use in deep-space transponders. The present frequency synthesizers contain advanced MMIC VCOs, which use HBT technology and have lower levels of flicker (1/f) phase noise. When these MMIC VCOs are used with high-speed MMIC frequency dividers, it becomes possible to obtain the required combination of frequency agility and low phase noise.

Condensing Heat Exchanger Concept Developed for Space Systems

NASA Technical Reports Server (NTRS)

Hasan, Mohammad M.; Nayagam, Vedha

2005-01-01

The current system for moisture removal and humidity control for the space shuttles and the International Space Station uses a two-stage process. Water first condenses onto fins and is pulled through "slurper bars." These bars take in a two-phase mixture of air and water that is then separated by the rotary separator. A more efficient design would remove the water directly from the air without the need of an additional water separator downstream. For the Condensing Heat Exchanger for Space Systems (CHESS) project, researchers at the NASA Glenn Research Center in collaboration with NASA Johnson Space Center are designing a condensing heat exchanger that utilizes capillary forces to collect and remove water and that can operate in varying gravitational conditions including microgravity, lunar gravity, and Martian gravity.

Space Shuttle 2 Advanced Space Transportation System. Volume 1: Executive Summary

NASA Technical Reports Server (NTRS)

Adinaro, James N.; Benefield, Philip A.; Johnson, Shelby D.; Knight, Lisa K.

1989-01-01

An investigation into the feasibility of establishing a second generation space transportation system is summarized. Incorporating successful systems from the Space Shuttle and technological advances made since its conception, the second generation shuttle was designed to be a lower-cost, reliable system which would guarantee access to space well into the next century. A fully reusable, all-liquid propellant booster/orbiter combination using parallel burn was selected as the base configuration. Vehicle characteristics were determined from NASA ground rules and optimization evaluations. The launch profile was constructed from particulars of the vehicle design and known orbital requirements. A stability and control analysis was performed for the landing phase of the orbiter's flight. Finally, a preliminary safety analysis was performed to indicate possible failure modes and consequences.

A Thermal Expert System (TEXSYS) development overview - AI-based control of a Space Station prototype thermal bus

NASA Technical Reports Server (NTRS)

Glass, B. J.; Hack, E. C.

1990-01-01

A knowledge-based control system for real-time control and fault detection, isolation and recovery (FDIR) of a prototype two-phase Space Station Freedom external thermal control system (TCS) is discussed in this paper. The Thermal Expert System (TEXSYS) has been demonstrated in recent tests to be capable of both fault anticipation and detection and real-time control of the thermal bus. Performance requirements were achieved by using a symbolic control approach, layering model-based expert system software on a conventional numerical data acquisition and control system. The model-based capabilities of TEXSYS were shown to be advantageous during software development and testing. One representative example is given from on-line TCS tests of TEXSYS. The integration and testing of TEXSYS with a live TCS testbed provides some insight on the use of formal software design, development and documentation methodologies to qualify knowledge-based systems for on-line or flight applications.

Experimental Evidence for a Structural-Dynamical Transition in Trajectory Space.

PubMed

Pinchaipat, Rattachai; Campo, Matteo; Turci, Francesco; Hallett, James E; Speck, Thomas; Royall, C Patrick

2017-07-14

Among the key insights into the glass transition has been the identification of a nonequilibrium phase transition in trajectory space which reveals phase coexistence between the normal supercooled liquid (active phase) and a glassy state (inactive phase). Here, we present evidence that such a transition occurs in experiments. In colloidal hard spheres, we find a non-Gaussian distribution of trajectories leaning towards those rich in locally favored structures (LFSs), associated with the emergence of slow dynamics. This we interpret as evidence for a nonequilibrium transition to an inactive LFS-rich phase. Reweighting trajectories reveals a first-order phase transition in trajectory space between a normal liquid and a LFS-rich phase. We also find evidence for a purely dynamical transition in trajectory space.

Adaptive array antenna for satellite cellular and direct broadcast communications

NASA Technical Reports Server (NTRS)

Horton, Charles R.; Abend, Kenneth

1993-01-01

Adaptive phased-array antennas provide cost-effective implementation of large, light weight apertures with high directivity and precise beamshape control. Adaptive self-calibration allows for relaxation of all mechanical tolerances across the aperture and electrical component tolerances, providing high performance with a low-cost, lightweight array, even in the presence of large physical distortions. Beam-shape is programmable and adaptable to changes in technical and operational requirements. Adaptive digital beam-forming eliminates uplink contention by allowing a single electronically steerable antenna to service a large number of receivers with beams which adaptively focus on one source while eliminating interference from others. A large, adaptively calibrated and fully programmable aperture can also provide precise beam shape control for power-efficient direct broadcast from space. Advanced adaptive digital beamforming technologies are described for: (1) electronic compensation of aperture distortion, (2) multiple receiver adaptive space-time processing, and (3) downlink beam-shape control. Cost considerations for space-based array applications are also discussed.

TH-EF-BRA-06: A Novel Retrospective 3D K-Space Sorting 4D-MRI Technique Using a Radial K-Space Acquisition MRI Sequence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Y; Subashi, E; Yin, F

Purpose: Current retrospective 4D-MRI provides superior tumor-to-tissue contrast and accurate respiratory motion information for radiotherapy motion management. The developed 4D-MRI techniques based on 2D-MRI image sorting require a high frame-rate of the MR sequences. However, several MRI sequences provide excellent image quality but have low frame-rate. This study aims at developing a novel retrospective 3D k-space sorting 4D-MRI technique using radial k-space acquisition MRI sequences to improve 4D-MRI image quality and temporal-resolution for imaging irregular organ/tumor respiratory motion. Methods: The method is based on a RF-spoiled, steady-state, gradient-recalled sequence with minimal echo time. A 3D radial k-space data acquisition trajectorymore » was used for sampling the datasets. Each radial spoke readout data line starts from the 3D center of Field-of-View. Respiratory signal can be extracted from the k-space center data point of each spoke. The spoke data was sorted based on its self-synchronized respiratory signal using phase sorting. Subsequently, 3D reconstruction was conducted to generate the time-resolved 4D-MRI images. As a feasibility study, this technique was implemented on a digital human phantom XCAT. The respiratory motion was controlled by an irregular motion profile. To validate using k-space center data as a respiratory surrogate, we compared it with the XCAT input controlling breathing profile. Tumor motion trajectories measured on reconstructed 4D-MRI were compared to the average input trajectory. The mean absolute amplitude difference (D) was calculated. Results: The signal extracted from k-space center data matches well with the input controlling respiratory profile of XCAT. The relative amplitude error was 8.6% and the relative phase error was 3.5%. XCAT 4D-MRI demonstrated a clear motion pattern with little serrated artifacts. D of tumor trajectories was 0.21mm, 0.23mm and 0.23mm in SI, AP and ML directions, respectively. Conclusion: A novel retrospective 3D k-space sorting 4D-MRI technique has been developed and evaluated on human digital phantom. NIH (1R21CA165384-01A1)« less

Experiment "Regeneration" Performed Aboard the Russian Spacecraft Foton-M2 in 2005

NASA Technical Reports Server (NTRS)

Grigoryan, Elonora; Almeida, Eduardo; Domaratskaya, Elena; Poplinskaya, Valentina; Aleinikova, Karina; Tairbekov, Murad; Mitashov, Victor

2006-01-01

The experiments on the newts performed earlier aboard Russian biosate llites showed that the rate of lens and tail regeneration in space wa s greater than on the ground. In parallel it was found that the numbe r of cells in S-phase was greater in space-flown animals than in the ground controls. However, it was unclear whether cell proliferation stimulation was induced by micro-g per se. Molecular mechanisms under lying the change also remained obscure. These issues were addressed b y the joint Russian-American experiment "Regeneration" flown on Foton -M2 in 2005. The method for in-flight delivering DNA precursor BrdU was developed. The experiment showed that during the flight the numbe r of S-phase cells in the regenerating eyes and tails increased. Thes e data together with those obtained earlier suggest that cell prolife ration increases in response to the effects of both micro-g and 1-g a fter return to Earth. The expression of bFGF in regenerating tissues of "flown" newts and ground controls was examined using immuno-histo chemistry. Obtained results suggest that this growth factor is a part icipant of the promotional effect of space flight upon cell prolifera tion in lens and tail regenerates.

A membrane-based subsystem for water-vapor recovery from plant-growth chambers

NASA Technical Reports Server (NTRS)

Ray, R. J.

1992-01-01

Bioregenerative systems--life-support systems to regenerate oxygen, food, and water--are the key to establishing man's permanent presence in space. NASA is investigating the use of plant-growth chambers (PGC's) for space missions and for bases on the moon and Mars. PGC's serve several important purposes, including the following: (1) oxygen and food production; (2) carbon-dioxide removal; and (3) water purification and reuse. The key to the successful development of PGC's is a system to recover and reuse the water vapor that is transpired by the leaves of the growing plants. In this program we propose to develop a simple, reliable, membrane-based system that allows the recovery, purification, and reuse of the transpired water vapor through control of temperature and humidity levels in the PGC. This system has characteristics that make it ideally suited to use in space: (1) minimal power requirements; (2) small volume and mass; (3) simplicity; (4) reliability; and (5) versatility. In Phase 1 we will do the following: (1) develop an accurate, predictive model of our temperature- and humidity-control system, based on parametric tests of membrane modules; and (2) use this model to design systems for selected PGC's. In Phase 2, we will seek to design, fabricate, test, and deliver a breadboard unit to NASA for testing on a PGC.